private static int checkMatrix(int[][] matrix) {
    int maxNegativeColumn = -1;
    columns:
        for (int j = matrix[0].length-1; j >= 0; j--) {
            for (int i = 0; i < matrix.length;i++){
                if (matrix[i][j] >= 0){
                    continue columns;
                }
            }
            maxNegativeColumn = j;
    }
    return maxNegativeColumn;
}