def search_in_a_sorted_matrix(mat, m, n, key):
    i, j = m - 1, 0
    while i >= 0 and j < n:
        if key == mat[i][j]:
            print("Key {} found at row- {} column- {}".format(key, i + 1, j + 1))
            return
        if key < mat[i][j]:
            i -= 1
        else:
            j += 1
    print("Key %s not found" % (key))


def main():
    mat = [[2, 5, 7], [4, 8, 13], [9, 11, 15], [12, 17, 20]]
    x = int(input("Enter the element to be searched:"))
    print(mat)
    search_in_a_sorted_matrix(mat, len(mat), len(mat[0]), x)


if __name__ == "__main__":
    main()