#include"bits/stdc++.h" using namespace std; #define REP(k,m,n) for(int (k)=(m);(k)<(n);(k)++) #define rep(i,n) REP((i),0,(n)) using ll = long long; class UnionFind { public: vectorrank, parent; //初期化 UnionFind(int size) { rank.resize(size, 0); parent.resize(size, 0); rep(i, size)parent[i] = i; } //木の根を求める int find(int x) { if (parent[x] == x)return x; else return parent[x] = find(parent[x]); } //xとyの属する集合を併合 void unite(int x, int y) { x = find(x); y = find(y); if (x == y)return; if (rank[x] < rank[y]) parent[x] = y; else { parent[y] = x; if (rank[x] == rank[y])rank[x]++; } } //xとyが同じ集合に属するか否か bool same(int x, int y) { return (find(x) == find(y)); } }; vector> edges; vector weight; vector> sizeSubtree; // {コスト和, 頂点の数} UnionFind uf(0); map tot; mapcent; void SubFindCentroids(int v, int parent_of_v = -1) { const int N = tot[uf.find(v)]; sizeSubtree[v] = { 0,weight[v] }; for (auto ch : edges[v]) { if (ch == parent_of_v) continue; SubFindCentroids(ch, v); auto res = sizeSubtree[ch]; res.first += res.second; sizeSubtree[v].first += res.first; sizeSubtree[v].second += res.second; } } int findCent(int now) { int cost, cnt; tie(cost, cnt) = sizeSubtree[now]; int w = weight[now]; int bcost = cost; int bpos = now; for (int next : edges[now]) { int ncost, ncnt; tie(ncost, ncnt) = sizeSubtree[next]; ncost = (cost - ncnt) + (cnt - ncnt); if (ncost < bcost) { bcost = ncost; bpos = next; } } if (now == bpos)return now; int ncost, ncnt; tie(ncost, ncnt) = sizeSubtree[bpos]; sizeSubtree[now] = { cost - ncost - ncnt,cnt - ncnt }; sizeSubtree[bpos] = { bcost, tot[uf.find(now)] }; return findCent(bpos); } using Graph = vector>; struct HLDecomposition { using pii = pair; int n; Graph G; vector vid, inv, par, depth, subsize, head, prev, next, type; HLDecomposition(const Graph& G_) : n(G_.size()), G(G_), vid(n, -1), inv(n), par(n), depth(n), subsize(n, 1), head(n), prev(n, -1), next(n, -1), type(n) {} void build(vector roots = { 0 }) { int curtype = 0, pos = 0; for (int root : roots) { decide_heavy_edge(root); reconstruct(root, curtype++, pos); } } void decide_heavy_edge(int root) { stack st; par[root] = -1, depth[root] = 0; st.emplace(root, 0); while (!st.empty()) { int now = st.top().first; int& way = st.top().second; if (way < G[now].size()) { int child = G[now][way++]; if (child == par[now])continue; par[child] = now; depth[child] = depth[now] + 1; st.emplace(child, 0); } else { st.pop(); int maxsize = 0; for (auto child : G[now]) { if (child == par[now])continue; subsize[now] += subsize[child]; if (maxsize < subsize[child]) { maxsize = subsize[child]; prev[child] = now; next[now] = child; } } } } } void reconstruct(int root, int curtype, int& pos) { stack st({ root }); while (!st.empty()) { int start = st.top(); st.pop(); for (int v = start; v != -1; v = next[v]) { type[v] = curtype; vid[v] = pos++; inv[vid[v]] = v; head[v] = start; for (auto child : G[v]) { if (child != par[v] && child != next[v]) { st.push(child); } } } } } // node query [u, v], f([left, right]) void foreach_nodes(int u, int v, const function& f) { while (true) { if (vid[u] > vid[v])swap(u, v); f(max(vid[head[v]], vid[u]), vid[v]); if (head[u] != head[v])v = par[head[v]]; else break; } } // edge query[u,v] f([left, right]) // seg_node[vid[i]] := edge(par[i] -> i) void foreach_edges(int u, int v, const function& f) { while (true) { if (vid[u] > vid[v])swap(u, v); if (head[u] != head[v]) { f(vid[head[v]], vid[v]); v = par[head[v]]; } else { if (u != v)f(vid[u] + 1, vid[v]); break; } } } int lca(int u, int v) { while (true) { if (vid[u] > vid[v])swap(u, v); if (head[u] == head[v])return u; v = par[head[v]]; } } }; int main() { int N, M, Q; cin >> N >> M >> Q; edges.resize(N); weight.resize(N); uf = UnionFind(N); sizeSubtree.resize(N); rep(i, M) { int u, v; cin >> u >> v; u--; v--; edges[u].push_back(v); edges[v].push_back(u); uf.unite(u, v); } vector> ab; rep(i, Q) { int a, b; cin >> a >> b; a--; b--; ab.push_back({ a,b }); if (!uf.same(a, b)) { weight[a]++; weight[b]++; tot[uf.find(a)]++; tot[uf.find(b)]++; } } { set st; rep(i, N) { int par = uf.find(i); if (st.find(par) != st.end())continue; st.insert(par); SubFindCentroids(i); cent[par] = findCent(i); } } HLDecomposition hld(edges); { set st; rep(i, N)st.insert(uf.find(i)); vector routes; for (int num : st)routes.push_back(num); hld.build(routes); } ll res = 0; for (auto route : ab) { int a, b; tie(a, b) = route; if (uf.same(a, b)) { int m = hld.lca(a, b); res += hld.depth[a] + hld.depth[b] - 2 * hld.depth[m]; } else { int from = cent[uf.find(a)]; assert(uf.same(a, from)); int m = hld.lca(a, from); res += hld.depth[a] + hld.depth[from] - 2 * hld.depth[m]; int to = cent[uf.find(b)]; m = hld.lca(b, to); res += hld.depth[b] + hld.depth[to] - 2 * hld.depth[m]; } } cout << res << endl; return 0; }