func_code_string: #include <bits/stdc++.h>   using namespace std;   long long p[1000100], h[1000100], g[1000100], ans;   int main() {     int m, n, x, y;     cin >> n >> m;     for (int i = 0; i <= n; i++) p[i] = (i ? p[i - 1] * 9 : 1);     while (m--) {       scanf( %d%d , &x, &y);       h[x] += p[y];       h[y] += p[x];     }     for (int i = 1; i <= n; i++) g[i] = h[i] + p[i];     sort(h + 1, h + n + 1);     for (int i = 1, cnt = 0; i <= n; i++)       if (h[i] == h[i - 1])         ans += cnt++;       else         cnt = 1;     sort(g + 1, g + n + 1);     for (int i = 1, cnt = 0; i <= n; i++)       if (g[i] == g[i - 1])         ans += cnt++;       else         cnt = 1;     cout << ans << endl;   }   