func_code_string: #include <bits/stdc++.h>   using namespace std;   inline int in() {     int res = 0;     char c;     int f = 1;     while ((c = getchar()) <  0  || c >  9 )       if (c ==  - ) f = -1;     while (c >=  0  && c <=  9 ) res = res * 10 + c -  0 , c = getchar();     return res * f;   }   const int N = 100010;   long long num[N], rd[N];   long long ans;   pair<int, int> a[N << 1];   int main() {     int n = in(), m = in();     for (int i = 1; i <= n; i++) {       num[i] = 1;     }     for (int i = 0; i < m; i++) {       a[i].first = in();       a[i].second = in();     }     sort(a, a + m);     for (int i = 0; i < m; i++) {       int x = a[i].first, y = a[i].second;       if (x > y) {         num[x] = max(num[x], num[y] + 1);       } else {         num[y] = max(num[y], num[x] + 1);       }       rd[x]++;       rd[y]++;     }     for (int i = 1; i <= n; i++) {       ans = max(ans, 1LL * num[i] * rd[i]);     }     cout << ans << endl;     return 0;   }   