#include <stdio.h>
#include <iostream>
using namespace std;
int n, m, segRez[3004];
int segm1[3004];
char segm2[6005];
int main()
{
    cin >> n >> m;
    for(int i = 0; i < n; ++i){
        gets_s(segm2);
        for(int j = 0; j < m; ++j){
            segRez[j] = segm1[j] + int(segm2[j<<1] - 48);
            segm1[j] = int(segm2[j<<1] - 48);
            if(j - 1 >= 0 && ((segRez[j - 1]|segRez[j])) == 3){
                cout << "No";
                return 0;
            }
        }
    }
    cout << "Yes";
}