```cpp
#include <iostream>
#include <vector>
using namespace std;
struct Edge {
int u, v;
};
int n, m;
vector<Edge> e;
vector<bool> vis;
bool find_edge(int u, int v) {
for (int i = 1; i <= m; ++i) {
if (e[i].u == u && e[i].v == v) {
return true;
}
}
return false;
}
void dfs(int u) {
if (vis[u]) return;
vis[u] = true;
for (int i = 1; i <= m; ++i) {
if (e[i].u == u) {
dfs(e[i].v);
}
}
}
int main() {
cin >> n >> m;
vis.resize(n + 1, false);
e.resize(m + 1);
for (int i = 1; i <= m; ++i) cin >> e[i].u >> e[i].v;
return 0;
}