gistfile1.txt

def func(row):
    return int(row.split()[k])


if __name__ == '__main__':
    n, m = map(int, input().split())
    rows = [input() for _ in range(n)]
    k = int(input())

    # for row in sorted(rows, key=lambda row: int(row.split()[k])):   #works
    for row in sorted(rows, key=func(row)):                           #doesn't work
        print(row)