func_code_string: #include <bits/stdc++.h>   using namespace std;   template <typename T>   ostream &operator<<(ostream &os, const vector<T> &v) {     os <<  { ;     string sep;     for (const auto &x : v) os << sep << x, sep =  ,  ;     return os <<  } ;   }   template <typename T, size_t size>   ostream &operator<<(ostream &os, const array<T, size> &arr) {     os <<  { ;     string sep;     for (const auto &x : arr) os << sep << x, sep =  ,  ;     return os <<  } ;   }   template <typename A, typename B>   ostream &operator<<(ostream &os, const pair<A, B> &p) {     return os <<  (  << p.first <<  ,   << p.second <<  ) ;   }   void dbg_out() { cerr << endl; }   template <typename Head, typename... Tail>   void dbg_out(Head H, Tail... T) {     cerr <<     << H;     dbg_out(T...);   }   const int INF = 1e9 + 5;   struct segment_change {     int to_add;     segment_change(int _to_add = 0) : to_add(_to_add) {}     void reset() { to_add = 0; }     bool has_change() const { return to_add != 0; }     segment_change combine(const segment_change &other) const {       return segment_change(to_add + other.to_add);     }   };   struct segment {     int minimum, count_of_min;     segment(int _minimum = INF, int _count_of_min = 0)         : minimum(_minimum), count_of_min(_count_of_min) {}     void apply(int, const segment_change &change) { minimum += change.to_add; }     void join(const segment &other) {       if (other.minimum < minimum)         *this = other;       else if (other.minimum == minimum)         count_of_min += other.count_of_min;     }     void join(const segment &a, const segment &b) {       *this = a;       join(b);     }     int get_goal_count(int goal) const {       return minimum == goal ? count_of_min : 0;     }   };   pair<int, int> right_half[32];   struct min_count_seg_tree {     int tree_n = 0;     vector<segment> tree;     vector<segment_change> changes;     min_count_seg_tree(int n = -1) {       if (n >= 0) init(n);     }     void init(int n) {       tree_n = 1;       while (tree_n < n) tree_n *= 2;       tree.assign(2 * tree_n, segment());       changes.assign(tree_n, segment_change());     }     void build(const vector<segment> &initial) {       int n = int(initial.size());       init(n);       assert(n <= tree_n);       for (int i = 0; i < n; i++) tree[tree_n + i] = initial[i];       for (int position = tree_n - 1; position > 0; position--)         tree[position].join(tree[2 * position], tree[2 * position + 1]);     }     void push_down(int position, int length) {       if (!changes[position].has_change()) return;       if (2 * position < tree_n) {         changes[2 * position] = changes[2 * position].combine(changes[position]);         changes[2 * position + 1] =             changes[2 * position + 1].combine(changes[position]);       }       tree[2 * position].apply(length / 2, changes[position]);       tree[2 * position + 1].apply(length / 2, changes[position]);       changes[position].reset();     }     void push_all(int a, int b) {       assert(0 <= a && a < b && b <= tree_n);       a += tree_n;       b += tree_n - 1;       for (int up = 31 - __builtin_clz(tree_n); up > 0; up--) {         int x = a >> up, y = b >> up;         push_down(x, 1 << up);         if (x != y) push_down(y, 1 << up);       }     }     void join_and_apply(int position, int length) {       tree[position].join(tree[2 * position], tree[2 * position + 1]);       tree[position].apply(length, changes[position]);     }     void join_all(int a, int b) {       assert(0 <= a && a < b && b <= tree_n);       a += tree_n;       b += tree_n - 1;       int length = 1;       while (a > 1) {         a /= 2;         b /= 2;         length *= 2;         join_and_apply(a, length);         if (a != b) join_and_apply(b, length);       }     }     template <typename T_range_op>     void process_range(int a, int b, bool needs_join, T_range_op &&range_op) {       if (a == b) return;       push_all(a, b);       int original_a = a, original_b = b;       int length = 1, r_size = 0;       for (a += tree_n, b += tree_n; a < b; a /= 2, b /= 2, length *= 2) {         if (a & 1) range_op(a++, length);         if (b & 1) right_half[r_size++] = {--b, length};       }       for (int i = r_size - 1; i >= 0; i--)         range_op(right_half[i].first, right_half[i].second);       if (needs_join) join_all(original_a, original_b);     }     segment query(int a, int b) {       assert(0 <= a && a <= b && b <= tree_n);       segment answer;       process_range(a, b, false,                     [&](int position, int) { answer.join(tree[position]); });       return answer;     }     void update(int a, int b, const segment_change &change) {       assert(0 <= a && a <= b && b <= tree_n);       process_range(a, b, true, [&](int position, int length) {         tree[position].apply(length, change);         if (position < tree_n)           changes[position] = changes[position].combine(change);       });     }   };   struct rectangle {     int x1, y1, x2, y2;   };   struct rect_event {     int x, y1, y2, change;     bool operator<(const rect_event &other) const { return x < other.x; }   };   int64_t rectangle_union_area(const vector<rectangle> &rects) {     if (rects.empty()) return 0;     vector<int> Xs, Ys;     vector<rect_event> events;     for (const rectangle &rect : rects) {       Xs.push_back(rect.x1);       Xs.push_back(rect.x2);       Ys.push_back(rect.y1);       Ys.push_back(rect.y2);       events.push_back({rect.x1, rect.y1, rect.y2, +1});       events.push_back({rect.x2, rect.y1, rect.y2, -1});     }     sort(Xs.begin(), Xs.end());     sort(Ys.begin(), Ys.end());     Xs.resize(unique(Xs.begin(), Xs.end()) - Xs.begin());     Ys.resize(unique(Ys.begin(), Ys.end()) - Ys.begin());     int XC = int(Xs.size());     int YC = int(Ys.size());     int Y_range = Ys.back() - Ys.front();     sort(events.begin(), events.end());     int E = int(events.size());     auto &&compress_y = [&](int y) {       return int(lower_bound(Ys.begin(), Ys.end(), y) - Ys.begin());     };     min_count_seg_tree tree(YC - 1);     vector<segment> initial(YC - 1);     for (int i = 0; i < YC - 1; i++) initial[i] = segment(0, Ys[i + 1] - Ys[i]);     tree.build(initial);     int64_t area = 0;     for (int i = 0, e = 0; i < XC - 1; i++) {       while (e < E && events[e].x <= Xs[i]) {         int y1 = compress_y(events[e].y1);         int y2 = compress_y(events[e].y2);         tree.update(y1, y2, segment_change(events[e].change));         e++;       }       segment result = tree.tree[1];       area += int64_t(Y_range - result.get_goal_count(0)) * (Xs[i + 1] - Xs[i]);     }     return area;   }   int N, M, NM;   vector<string> grid;   vector<int> slides_to;   vector<vector<int>> adj;   vector<int> tour_start, tour_end;   int tour;   bool valid(int r, int c) { return 0 <= r && r < N && 0 <= c && c < M; }   int key(int r, int c) { return valid(r, c) ? r * M + c : -1; };   void dfs(int node, int parent) {     tour_start[node] = tour++;     for (int neigh : adj[node])       if (neigh != parent) dfs(neigh, node);     tour_end[node] = tour;   }   int main() {     ios::sync_with_stdio(false);     cin.tie(nullptr);     cin >> N >> M;     NM = N * M;     grid.resize(N);     for (string &row : grid) cin >> row;     slides_to.assign(NM, -1);     for (int r = 0; r < N; r++)       for (int c = 0; c < M; c++) {         int me = key(r, c);         switch (grid[r][c]) {           case  L :             slides_to[me] = key(r, c + 2);             break;           case  R :             slides_to[me] = key(r, c - 2);             break;           case  U :             slides_to[me] = key(r + 2, c);             break;           case  D :             slides_to[me] = key(r - 2, c);             break;         }       }     adj.assign(NM, {});     for (int i = 0; i < NM; i++)       if (slides_to[i] >= 0) adj[slides_to[i]].push_back(i);     tour_start.assign(NM, -1);     tour_end.assign(NM, -1);     tour = 0;     for (int i = 0; i < NM; i++)       if (slides_to[i] < 0) dfs(i, -1);     vector<rectangle> rects;     for (int r = 0; r < N; r++)       for (int c = 0; c < M; c++)         if (grid[r][c] ==  L  || grid[r][c] ==  U ) {           int key0 = key(r, c);           int key1 = grid[r][c] ==  L  ? key(r, c + 1) : key(r + 1, c);           if ((r + c) % 2 != 0) swap(key0, key1);           rects.push_back({tour_start[key0], tour_start[key1], tour_end[key0],                            tour_end[key1]});         }     cout << rectangle_union_area(rects) <<   n ;   }   