func_code_string: #include <bits/stdc++.h>   using namespace std;   const int N = 5010;   int n, m, s;   vector<int> e[N];   int low[N], dfn[N], idx;   bool vis[N];   stack<int> st;   bool in_stack[N];   int color[N], color_tot;   int indeg[N];   int ans;   void AddEdge(int u, int v) { e[u].push_back(v); }   void Dfs(int u) {     low[u] = dfn[u] = ++idx;     in_stack[u] = true;     st.push(u);     for (int v : e[u]) {       if (!dfn[v]) {         Dfs(v);         low[u] = min(low[u], low[v]);       } else if (in_stack[v]) {         low[u] = min(low[u], dfn[v]);       }     }     if (low[u] == dfn[u]) {       ++color_tot;       int v;       do {         v = st.top();         st.pop();         in_stack[v] = false;         color[v] = color_tot;       } while (v != u);     }   }   void Tarjan() {     for (int i = 1; i <= n; ++i)       if (!color[i]) Dfs(i);   }   int main() {     scanf( %d%d%d , &n, &m, &s);     for (int i = 1; i <= m; ++i) {       int u, v;       scanf( %d%d , &u, &v);       AddEdge(u, v);     }     Tarjan();     for (int i = 1; i <= n; ++i)       ;     for (int i = 1; i <= n; ++i)       for (int j : e[i])         if (color[i] != color[j]) ++indeg[color[j]];     for (int i = 1; i <= color_tot; ++i)       ;     for (int i = 1; i <= color_tot; ++i)       if (indeg[i] == 0) ++ans;     if (indeg[color[s]] == 0) --ans;     printf( %d n , ans);     return 0;   }   