#include<bits/stdc++.h>
using namespace std;
#define int long long
#define f(i, a, b) for(int i = (a); i <= (b); i++)
char c[2020][2020]; int n; 
bool even(int x,int y){return (c[x][y]^c[x-1][y]^c[x-1][y-1]^c[x-2][y-1]) == 0;}
bool blank(int x,int y){return c[x][y]==0&&c[x-1][y]==0&&c[x-1][y-1]==0&&c[x-2][y-1]==0;}
void flip(int x,int y){return c[x][y]^=1, void();}
void modify(int x) {f(i,1,x){flip(x,i);} return;}
void judge() {f(i,3,n){int stt=even(i,2);f(j,3,i-1){if(stt!=even(i,j))return;}if(stt){modify(i);}}cout<<"YES\n";exit(0);}
signed main() {
    cin >> n; f(i,1,n)f(j,1,i){cin>>c[i][j];c[i][j]-='0';}
    judge(); modify(1); judge(); modify(2); judge(); modify(1); judge();
    cout << "NO\n";
    return 0;
}