#include <iostream>
using namespace std;
 
const int MAX_SIZE = 9;
 
int main() {
    int lineSize, colSize;
    cin >> lineSize >> colSize;
    int mt[MAX_SIZE +1][MAX_SIZE + 1], areEqual = 1;
    for (int line = 1; line <= colSize; ++line) {
        for (int col = 1; col <= lineSize; ++col) {
            cin >> mt[line][col];
            if (((col == lineSize / 2 + 1 && mt[line][col] != 
                mt[1][lineSize / 2 + 1]) || (line == colSize / 2 + 1 && 
                mt[line][col] != mt[1][lineSize / 2 + 1])) && areEqual == 1) {
                areEqual = 0;
            }
        }
    }
    if (areEqual == 1) {
        cout << "Da";
    } else {
        cout << "Nu";
    }
    return 0;
}

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NSA1CjEgMiAzIDQgNQoxIDIgMyA0IDUKMyAzIDMgMyAzCjEgMiAzIDQgNSAKMSAyIDMgNCA1

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1 2 3 4 5
1 2 3 4 5
3 3 3 3 3
1 2 3 4 5 
1 2 3 4 5