static String solve(List> board) {

    for (int i = 0; i < board.size()-1; i++) {
        List<Integer> row = board.get(i);
        List<Integer> col1 = board.get(i+1);
        int col=0;
        for (int k = 1; k < row.size(); k++) {
            int val = row.get(k);
            if(val==row.get(col)) {
                return "No";
            }
            else {
                col++;
            }
        }

        for (int k = 0; k < row.size(); k++) {
            int val1=col1.get(k);
            int val = row.get(k);
            if(val==val1) {
                return "No";
            }
        }


    }
    return "Yes";
}