#include #include #include #include using namespace std; #pragma comment(linker, "/STACK:102400000,102400000") const int maxn = 1000005; int N,M1,M2,cnt; int fa[maxn],vis[maxn]; vectorG[maxn]; int find_father(int u){ return u == fa[u] ? u : fa[u] = find_father(fa[u]); } void init(){ for(int i = 1; i <= N; i++) fa[i] = i; for(int i = 1; i <= N; i++) G[i].clear(); } bool dfs(int v){ vis[v] = -1; for(int i = 0; i < G[v].size(); i++){ int e = G[v][i]; if(vis[e] < 0) return false; if(!vis[e] && !dfs(e)) return false; } vis[v] = 1; return true; } int solve(){ memset(vis,0,sizeof(vis)); for(int i = 1; i <= N; i++){ int e = find_father(i); if(!vis[e]){ if(!dfs(e)) return true; } } return false; } int main(){ int T; scanf("%d",&T); while(T--){ scanf("%d%d%d",&N,&M1,&M2); int u,v,ok = 0; init(); getchar(); for(int i = 0; i < M1; i++){ scanf("%d%d",&u,&v); int f1 = find_father(u); int f2 = find_father(v); if(f1 == f2) ok = 1; else fa[f1] = f2; } for(int i = 0; i < M2; i++){ scanf("%d%d",&u,&v); if(!ok){ int f1 = find_father(u); int f2 = find_father(v); G[f1].push_back(f2); } } if(ok) printf("YES\n"); else{ ok = solve(); if(ok) printf("YES\n"); else printf("NO\n"); } } return 0; }