#include <bits/stdc++.h>

using namespace std;
const int N = 110;
char a[N][N];
#define x first
#define y second
typedef pair<int, int> PII;
int dx[] = {-1, 0, 1, 0}; //上右下左
int dy[] = {0, 1, 0, -1}; //上右下左
int main() {
    int n, m;
    cin >> n >> m;
    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= m; j++)
            cin >> a[i][j];

    queue<PII> q;
    q.push({1, 1});
    while (q.size()) {
        auto t = q.front();
        q.pop();
        for (int i = 0; i < 4; i++) {
            int tx = t.x + dx[i], ty = t.y + dy[i];
            if (tx == 0 || tx > n || ty == 0 || ty > m) continue;
            if (a[tx][ty] == '0') {
                a[tx][ty] = 'x';
                q.push({tx, ty});
            }
        }
    }

    if (a[n][m] == 'x')
        cout << "yes" << endl;
    else
        cout << "no" << endl;
    return 0;
}