import re

n = int(input())
queue = []

valid = True
for _ in range(n):
    name = input().strip()
    if not re.match("^[A-Za-z0-9]+$", name):
        valid = False
    queue.append(name)  # enqueue

if valid:
    print(" ".join(queue))  # dequeue all in order
else:
    print("Invalid input")