func_code_string: #include <bits/stdc++.h>   namespace IO {   inline char gc() {     static const int Rlen = 1 << 22 | 1;     static char buf[Rlen], *p1, *p2;     return (p1 == p2) && (p2 = (p1 = buf) + fread(buf, 1, Rlen, stdin), p1 == p2)                ? EOF                : *p1++;   }   template <typename T>   T get_integer() {     char c;     bool f = false;     while (!isdigit(c = gc())) f = c ==  - ;     T x = c ^ 48;     while (isdigit(c = gc())) x = ((x + (x << 2)) << 1) + (c ^ 48);     return f ? -x : x;   }   inline int gi() { return get_integer<int>(); }   }  // namespace IO   using namespace IO;   using std::cerr;   using std::cout;   using pii = std::pair<int, int>;   const int N = 1.5e5 + 7;   int n, m, k;   long long ans;   std::vector<int> G[N];   std::vector<pii> Q[N];   int fa[N], in[N], out[N];   int sz[N], son[N], top[N];   int d[N], ps[N], dfc;   void dfs1(int u, int p) {     fa[u] = p, d[u] = d[p] + 1;     for (int v : G[u])       if (v != p) {         dfs1(v, u);         sz[u] += sz[v];         if (sz[v] > sz[son[u]]) son[u] = v;       }     ++sz[u];   }   void dfs2(int u, int tp) {     top[u] = tp;     ps[in[u] = ++dfc] = u;     if (son[u]) dfs2(son[u], tp);     for (int v : G[u])       if (v != fa[u] && v != son[u]) dfs2(v, v);     out[u] = dfc;   }   int LCA(int u, int v) {     while (top[u] != top[v])       d[top[u]] < d[top[v]] ? v = fa[top[v]] : u = fa[top[u]];     return d[u] < d[v] ? u : v;   }   int jump(int u, int k) {     while (k > d[u] - d[top[u]]) {       k -= d[u] - d[top[u]] + 1;       u = fa[top[u]];     }     return ps[in[u] - k];   }   namespace SGT {   const int N = ::N * 40;   int lc[N], rc[N], sm[N], ct;   void ins(int &u, int l, int r, int p) {     if (!u) u = ++ct;     ++sm[u];     if (l == r) return;     int m = (l + r) >> 1;     p <= m ? ins(lc[u], l, m, p) : ins(rc[u], m + 1, r, p);   }   int qy(int u, int l, int r, int ql, int qr) {     if ((ql <= l && r <= qr) || !u) return sm[u];     int m = (l + r) >> 1;     if (qr <= m) return qy(lc[u], l, m, ql, qr);     if (m < ql) return qy(rc[u], m + 1, r, ql, qr);     return qy(lc[u], l, m, ql, qr) + qy(rc[u], m + 1, r, ql, qr);   }   void merge(int &u, int v) {     if (!u || !v) {       u |= v;       return;     }     merge(lc[u], lc[v]);     merge(rc[u], rc[v]);     sm[u] += sm[v];   }   void ins(int &u, int p) { ins(u, 1, n, p); }   int qy(int u, int l, int r) { return qy(u, 1, n, l, r); }   void clear() {     while (ct) lc[ct] = rc[ct] = sm[ct] = 0, --ct;   }   }  // namespace SGT   namespace BIT {   int tr[N];   void add(int l, int r) {     for (int register p = l; p <= n; p += p & -p) ++tr[p];     for (int register p = r + 1; p <= n; p += p & -p) --tr[p];   }   int qy(int p) {     int r = 0;     for (; p; p &= p - 1) r += tr[p];     return r;   }   }  // namespace BIT   int rt[N];   std::vector<int> q[N];   void solve_q(int u, int Rt) {     rt[u] = 0;     int od = std::max(0, k - d[u] + d[Rt]);     for (int v : q[u]) {       if (d[v] >= od + d[Rt]) {         int p = jump(v, d[v] - d[Rt] - od);         ans += SGT::qy(rt[u], in[p], out[p]);       }       SGT::ins(rt[u], in[v]);     }     for (int w : G[u])       if (Rt != u || w != son[u]) {         solve_q(w, Rt);         if (q[w].size() > q[u].size()) q[u].swap(q[w]), std::swap(rt[u], rt[w]);         for (int v : q[w]) {           if (d[v] >= od + d[Rt]) {             int p = jump(v, d[v] - d[Rt] - od);             ans += SGT::qy(rt[u], in[p], out[p]);           }           q[u].push_back(v);         }         q[w].clear();         SGT::merge(rt[u], rt[w]);       }   }   void solve(int u) {     for (int v : G[u]) solve(v);     for (auto &t : Q[u]) ans += BIT::qy(in[t.second]);     for (auto &t : Q[u])       if (d[t.second] >= d[u] + k) {         int p = jump(t.second, d[t.second] - d[u] - k);         BIT::add(in[p], out[p]);       }     for (auto &t : Q[u]) ans += BIT::qy(in[t.first]);     for (auto &t : Q[u])       if (d[t.first] >= d[u] + k) {         int p = jump(t.first, d[t.first] - d[u] - k);         BIT::add(in[p], out[p]);       }     for (auto &t : Q[u]) q[t.first].push_back(t.second);     solve_q(u, u);     q[u].clear();     SGT::clear();   }   void Main() {     n = gi(), m = gi(), k = gi();     for (int register i = 1; i < n; ++i) {       int u = gi(), v = gi();       G[u].push_back(v);       G[v].push_back(u);     }     dfs1(1, 0);     dfs2(1, 1);     for (int register i = 2; i <= n; ++i)       G[i].erase(std::find(G[i].begin(), G[i].end(), fa[i]));     for (int register i = 1; i <= m; ++i) {       int u = gi(), v = gi();       if (in[u] > in[v]) std::swap(u, v);       if (in[v] > out[u]) std::swap(u, v);       Q[LCA(u, v)].push_back({u, v});     }     solve(1);     cout << ans <<   n ;   }   inline void file() {}   signed main() {     file();     Main();     return 0;   }   