#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
 
using namespace std;
 
const int dx[] = {-1, 0, +1, 0};
const int dy[] = {0, -1, 0, +1};
bool dfs(vector<string> &f, int n, int r, int c, int m)
{
    const int rows = f.size();
    const int cols = f[0].size();
    if (m == n) {
        return true;
    }
    for (int k = 0; k < 4; ++k) {
        int r2 = r + dy[k];
        int c2 = c + dx[k];
        if (r2 < 0 || rows <= r2 || c2 < 0 || cols < c2) {
            continue;
        }
        if (f[r2][c2] != '0') {
            continue;
        }
        f[r2][c2] = '2';
        if (dfs(f, n, r2, c2, m + 1)) {
            return true;
        }
        f[r2][c2] = '0';
    }
    return false;
}
 
int main()
{
    int rows, cols;
    while (cin >> rows >> cols) {
        vector<string> f(rows);
        for (auto &s : f) {
            cin >> s;
            cout << s << endl;
        }
        int n = 0;
        int sr = -1, sc = -1;
        for (int i = 0; i < rows; ++i) {
            for (int j = 0; j < cols; ++j) {
                if (f[i][j] == '0') {
                    ++n;
                }
                if (f[i][j] == '2') {
                    sr = i;
                    sc = j;
                }
            }
        }
        if (dfs(f, n, sr, sc, 0)) {
            cout << "OK" << endl;
        } else {
            cout << "NG" << endl;
        }
        cout << endl;
    }
}
 

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