#include <bits/stdc++.h>   int main() {     int x;     int n, m;     scanf( %d %d , &n, &m);     if (m == 3 && n > 4) {       printf( -1 n );       return 0;     }     for (x = 0; x < m; ++x) printf( %d %d n , x, x * x + 10001);     for (x = 0; x < n - m; ++x) printf( %d %d n , x, -x * x);     return 0;   }   