#include<bits/stdc++.h>
using namespace std;
namespace file_read{
    namespace input_file_io{
        char ib[1<<25],*ip1=ib,*ip2=ib;
        inline char gc(){
#ifndef ONLINE_JUDGE
			return getchar();
#else
            return (ip1==ip2&&(ip2=(ip1=ib)+fread(ib,1,1<<24,stdin)),ip1==ip2?EOF:*ip1++);
#endif
        }
        inline int read(){
            int x=0;
            char c=gc();
            while(c<'0'||c>'9')c=gc();
            while(c>='0'&&c<='9'){
                x=(x<<3)+(x<<1)+(c^'0');
                c=gc();
            }
            return x;
        }
        inline int getch(){
			char c=gc();
			while(c!='0'&&c!='1')c=gc();
			return c-'0';
		}
    };
    namespace output_file_io{
        char ob[1<<25],*op=ob;
        inline void pc(char c){
            *op++=c;
        }
        void write(int x){
            if(x<0){
                pc('-');
                x=-x;
            }
            if(x==0)pc('0');
            static int number_stack[40];
            int total_count=0;
            while(x)number_stack[++total_count]=x%10,x/=10;
            while(total_count){
                pc(number_stack[total_count]+'0');
                --total_count;
            }
        }
        inline void final_write(){
            fwrite(ob,op-ob,1,stdout);
    	}
    };
	using namespace input_file_io;
	using namespace output_file_io;
};
using namespace file_read;
int m,n;
int mb[4][2]={{0,1},{0,-1},{1,0},{-1,0}};
bool ks[1<<11][1<<11];
bool dd[1<<22];
int tx[1<<22],ty[1<<22];
int gg[1<<22],tt=0;
void suan(int mm,int yx,int yy){
	if(mm==n){
		tx[tt]=yx,ty[tt]=yy;gg[tt++]=0;
		return;
	}
	for(int t=0;t<2;++t)for(int i=yx+t*mm;i<n;i+=(mm<<1))for(int j=yy+t*mm;j<n;j+=(mm<<1)){
		tx[tt]=i,ty[tt]=j;gg[tt++]=mm;
		for(int k=0;k<4;++k)ks[(i+mb[k][0]*mm+n)%n][(j+mb[k][1]*mm+n)%n]^=ks[i][j];
	}
	suan(mm<<1,yx+mm,yy),suan(mm<<1,yx,yy+mm);
}
int main(){
	m=read();n=1<<m;
	for(int i=0;i<n;++i)for(int j=0;j<n;++j)ks[i][j]=getch();
	suan(1,0,0);
	for(int i=tt-1;i>=0;--i){
		int wz=tx[i]*n+ty[i];
		dd[wz]=ks[tx[i]][ty[i]];
		if(!gg[i])continue;
		for(int k=0;k<4;++k){
			int dx=(tx[i]+mb[k][0]*gg[i]+n)%n,dy=(ty[i]+mb[k][1]*gg[i]+n)%n;
			dd[wz]^=dd[dx*n+dy];
		}
	}
	int cnt=0;
	for(int i=0;i<n;++i)for(int j=0;j<n;++j)cnt+=dd[i*n+j];
	write(cnt),pc('\n');
	for(int i=0;i<n;++i)for(int j=0;j<n;++j)if(dd[i*n+j])
		write(i),pc(' '),write(j),pc('\n');
	final_write();
	return 0;
}