func_code_string: #include <bits/stdc++.h>   using namespace std;   int n, m, s, ans = 0, f[2 * 200005];   inline int find(int x) { return f[x] == x ? x : f[x] = find(f[x]); }   int main() {     scanf( %d%d%d , &n, &m, &s);     for (register int i = 1; i <= m + n; i++) f[i] = i;     for (register int i = 1; i <= s; i++) {       register int a, b;       scanf( %d%d , &a, &b), b += n;       f[find(b)] = find(a);     }     for (register int i = 1; i <= n + m; i++)       if (f[i] == i) ans++;     printf( %d , ans - 1);     return 0;   }   