func_code_string: #include <bits/stdc++.h>   using namespace std;   const int maxn = 4e5 + 5;   int fa[maxn];   int m, n, q, i, x, y;   int getfa(int x) {     if (x == fa[x]) return x;     return fa[x] = getfa(fa[x]);   }   int main() {     scanf( %d%d%d , &n, &m, &q);     for (i = 1; i <= m + n; i++) fa[i] = i;     for (i = 1; i <= q; i++) {       scanf( %d%d , &x, &y);       fa[getfa(x)] = getfa(y + n);     }     int num = 0;     for (i = 1; i <= m + n; i++) {       if (fa[i] == i) num++;     }     cout << num - 1 << endl;   }   