#include <bits/stdc++.h>   using namespace std;   int main() {     int n, m;     scanf( %d%d , &n, &m);     if (m == 3 && (n == 5 || n == 6)) {       printf( -1 n );       return 0;     }     for (int i = 0; i < m; ++i) printf( %d %d n , i, i * i + 10000000);     for (int i = 0; i < n - m; ++i) printf( %d %d n , i, -i * i - 10000000);     return 0;   }   