func_code_string: #include <bits/stdc++.h>   using namespace std;   long long n, m, v, k, cnt;   signed main() {     scanf( %lld%lld%lld , &n, &m, &v), k = (v == 1) ? 2 : 1;     if (m < n - 1 || m > n - 1 + (n - 2) * (n - 3) / 2) puts( -1 ), exit(0);     for (long long i = 1; i <= n; i++)       if (i != v) printf( %lld %lld n , i, v);     cnt = n - 1;     for (long long i = 1; i <= n; i++) {       if (i == v || i == k) continue;       for (long long j = i + 1; j <= n; j++) {         if (j == v || j == k) continue;         if (cnt + 1 <= m) cnt++, printf( %lld %lld n , i, j);         if (cnt == m) break;       }     }     return 0;   }   