#include<bits/stdc++.h>
#define LL long long
#define LLL __int128
#define uint unsigned
#define ldb long double
#define uLL unsigned long long
using namespace std;
const int N=2050;
int n,m,ans;
bitset<N>a[N],b[N];
signed main(){
    cin.tie(0)->sync_with_stdio(0);
#define LOCAL
#ifndef LOCAL
    freopen(".in","r",stdin);
    freopen(".out","w",stdout);
#endif
    cin>>n,m=1<<n;
    for(int i=0;i<m;++i)
        for(int j=0,v;j<m;++j)
            cin>>v,a[i][j]=v;
    for(int k=1;k<=m;k*=2){
        for(int i=0;i<m;++i)b[i]=a[i];
        for(int i=0;i<m;++i)
            for(int j=0;j<m;++j)if(b[i][j])
                a[i].flip((j-1)&(m-1)),
                a[i].flip((j+1)&(m-1)),
                a[(i-1)&(m-1)].flip(j),
                a[(i+1)&(m-1)].flip(j);
    }
    for(int i=0;i<m;++i)ans+=a[i].count();
    cout<<ans<<'\n';
    for(int i=0;i<m;++i)
        for(int j=a[i]._Find_first();j<m;j=a[i]._Find_next(j))
            cout<<i<<' '<<j<<'\n';
    return 0;
}
/*
*/