func_code_string: #include <bits/stdc++.h>   using namespace std;   struct LazySegTree {     int size;     vector<long long> seg, delay;     LazySegTree() {}     LazySegTree(int size) {       this->size = size;       seg.resize(1 << (size + 1));       delay.resize(1 << (size + 1));     }     long long Ident() { return 0; }     long long ope(long long a, long long b) { return (a + b); }     void init() {       for (int i = 0; i < (1 << (size + 1)); i++) {         seg[i] = Ident();         delay[i] = 0;       }     }     void eval(int l, int r, int k) {       if (delay[k]) {         seg[k] = 0;         if (l < r) {           delay[k * 2] += delay[k];           delay[k * 2 + 1] += delay[k];         }         delay[k] = 0;       }     }     void update(int i, long long val) {       int l = 0, r = (1 << size) - 1, k = 1;       eval(l, r, k);       for (int j = size - 1; j >= 0; j--) {         k <<= 1;         if (i & (1 << j)) {           k++;           l = (l + r) / 2 + 1;         } else           r = (l + r) / 2;         eval(l, r, k);       }       seg[i + (1 << size)] = val;       l = i, r = i, k = i + (1 << size);       for (int j = 0; j < size; j++) {         k /= 2, l &= ~(1 << j), r |= 1 << j;         eval(l, (l + r) / 2, k * 2), eval((l + r) / 2 + 1, r, k * 2 + 1);         seg[k] = ope(seg[k * 2], seg[k * 2 + 1]);       }     }     void add(int a, int b, int k, int l, int r, long long val) {       eval(l, r, k);       if (b < l || r < a) return;       if (a <= l && r <= b) {         delay[k] += val;         eval(l, r, k);         return;       }       add(a, b, k * 2, l, (l + r) / 2, val);       add(a, b, k * 2 + 1, (l + r) / 2 + 1, r, val);       seg[k] = ope(seg[k * 2], seg[k * 2 + 1]);     }     void add(int a, int b, long long val) {       if (a > b) return;       add(a, b, 1, 0, (1 << size) - 1, val);     }     long long query(int a, int b, int k, int l, int r) {       eval(l, r, k);       if (b < l || r < a) return Ident();       if (a <= l && r <= b) return seg[k];       long long lval = query(a, b, k * 2, l, (l + r) / 2);       long long rval = query(a, b, k * 2 + 1, (l + r) / 2 + 1, r);       return ope(lval, rval);     }     long long query(int a, int b) {       if (a > b) return Ident();       return query(a, b, 1, 0, (1 << size) - 1);     }   };   long long n, m;   long long l[200005], r[200005], rcnt[200005];   vector<long long> vec[200005];   LazySegTree sseg[2], nseg[2];   multiset<long long> S[2];   long long dif[200005];   int main(void) {     ios::sync_with_stdio(0);     cin.tie(0);     cin >> n >> m;     for (long long(i) = (1); (i) <= (n); (i)++) {       cin >> l[i] >> r[i];       dif[l[i]]++, dif[r[i] + 1]--;       l[i]--;       vec[l[i]].push_back(r[i]);       rcnt[r[i]]++;     }     for (long long(i) = (0); (i) <= (1); (i)++) {       sseg[i] = LazySegTree(18), sseg[i].init();       nseg[i] = LazySegTree(18), nseg[i].init();     }     for (long long(i) = (0); (i) <= (m); (i)++)       sseg[i % 2].update(i, i), nseg[i % 2].update(i, 1);     long long ans = 0;     for (long long i = m; i >= 0; i--) {       for (auto r : vec[i]) {         sseg[i % 2].add(i + 1, r, 1), nseg[i % 2].add(i + 1, r, 1);         if ((r - i) % 2 == 0) {           sseg[0].add(r + 1, m, 1), sseg[1].add(r + 1, m, 1);           nseg[0].add(r + 1, m, 1), nseg[1].add(r + 1, m, 1);         }         S[r % 2].erase(S[r % 2].lower_bound(r));       }       long long lb = i, ub = m;       for (long long(j) = (0); (j) <= (1); (j)++)         if (S[j].size()) (lb) = max((lb), (*S[j].rbegin()));       if (S[i % 2].size()) (ub) = min((ub), (*S[i % 2].begin()));       ans += sseg[i % 2].query(lb + 1, ub);       ans += sseg[(i + 1) % 2].query(i + 1, ub);       ans -= i * nseg[i % 2].query(lb + 1, ub);       ans -= i * nseg[(i + 1) % 2].query(i + 1, ub);       for (long long(j) = (1); (j) <= (rcnt[i]); (j)++) S[i % 2].insert(i);     }     for (long long(i) = (1); (i) <= (m); (i)++) dif[i] += dif[i - 1];     dif[m + 1] = 1;     long long cnt = 0;     for (long long(i) = (1); (i) <= (m + 1); (i)++) {       if (dif[i])         ans -=             (cnt + 1) * cnt * (cnt + 1) / 2 - cnt * (cnt + 1) * (2 * cnt + 1) / 6,             cnt = 0;       else         cnt++;     }     cout << ans << endl;     return 0;   }   