#include<bits/stdc++.h>
using namespace std;
const int N=4097;

int n;
int mp[((N-1)/2)+1][(N-1)/2];

bitset<N> rw[2][(N-1)/2],mtx[N],trs[(N-1)/2];

int fir[N];
bool ans[(N-1)/2][(N-1)/2];

vector<pair<int,int> > vec;

int main(){
	//freopen("set.in","r",stdin);
	//freopen("set.out","w",stdout);
	ios::sync_with_stdio(false);
	cin>>n;
	for(int i=0;i<(1<<n);++i){
		for(int j=0;j<(1<<n);++j){
			cin>>mp[i][j];
			if(i==0){
				mp[1<<n][j]=mp[i][j];
			}
		}
	}
	for(int i=0;i<(1<<n);++i){
		rw[0][i][i]=1;
	}
	for(int i=0;i<(1<<n);++i){
		rw[1][i][i+(1<<n)]=1;
	}
	for(int i=2;i<=(1<<n)+1;++i){
		int pre1,pre2;
		pre1=(i&1)^1;
		pre2=pre1^1;
		for(int j=0;j<(1<<n);++j){
			trs[j]=rw[pre1][j]^rw[pre2][j]^rw[pre1][(j+1)&((1<<n)-1)]^rw[pre1][j==0?(1<<n)-1:j-1];
			if(mp[i-1][j]) trs[j][N-1]=trs[j][N-1]^1;
		}
		swap(rw[pre2],trs);
	}
	for(int i=0;i<(1<<n);++i){
		mtx[i]=rw[0][i];
		mtx[i][i]=mtx[i][i]^1;
	}
	for(int i=0;i<(1<<n);++i){
		mtx[i+(1<<n)]=rw[1][i];
		mtx[i+(1<<n)][i+(1<<n)]=mtx[i+(1<<n)][i+(1<<n)]^1;
	}
	int cur=0;
	for(int i=0;i<(1<<(n+1));++i){
		int trw=-1;
		for(int j=cur;j<(1<<(n+1));++j){
			if(mtx[j][i]){
				trw=j;
				break;
			}
		}
		if(trw==-1) continue;
		if(cur!=trw){
			swap(mtx[cur],mtx[trw]);
		}
		fir[cur]=i;
		for(int j=0;j<(1<<(n+1));++j){
			if(j==cur) continue;
			if(mtx[j][i]) mtx[j]^=mtx[cur];
		}
		++cur;
	}
	//bool flag=true;
	for(int i=0;i<(1<<(n+1));++i){
		if(i<cur){
			int id=fir[i];
			int rid;
			if(id>=(1<<n)){
				id-=(1<<n);
				rid=1;
			}
			else rid=0;
			ans[rid][id]=mtx[i][N-1];
			if(ans[rid][id]) vec.emplace_back(make_pair(rid,id));
		}
		else{
			if(mtx[i][N-1]){
				cout<<-1;
				return 0;
			}
		}
	}
	for(int i=2;i<(1<<n);++i){
		for(int j=0;j<(1<<n);++j){
			ans[i][j]=ans[i-1][j]^ans[i-2][j]^ans[i-1][(j+1)&((1<<n)-1)]^ans[i-1][j==0?(1<<n)-1:j-1];
			if(mp[i-1][j]) ans[i][j]^=1;
			if(ans[i][j]) vec.emplace_back(make_pair(i,j));
		}
	}
	cout<<vec.size()<<endl;
	for(auto p:vec){
		cout<<p.first<<' '<<p.second<<'\n';
	}
	/*for(int i=0;i<(1<<n);++i){
		for(int j=0;j<(1<<n);++j){
			cout<<ans[i][j]<<' ';
		}
		cout<<endl;
	}*/
	return 0;
}