#include <cstdio>

int main(){
    freopen("tije.in","r",stdin);
    freopen("tije.out","w",stdout);

    int i,j,z,N;

    scanf("%d",&N);
    for(i = 1; i < N; ++i)
    {
        for(j = 1; j < N; ++j) printf("%d %d\n", i, N+1);

        for(j = 1; j <= i; ++j) printf("%d %d\n", i+1, i);

        for(j = i+2; j <= N; ++j)
        {
            for(z = 1; z <= i-1; ++z) printf("%d %d\n", j, j-1 );
            printf("%d %d\n", j, i );
        }

        for(j = 1; j <= i-1; ++j) printf("%d %d\n", N+1, N);
        for(j = i+1; j <= N; ++j) printf("%d %d\n", N+1, j);
    }



return 0;
}