You are given a string *q*. A sequence of *k* strings *s*<sub class="lower-index">1</sub>, *s*<sub class="lower-index">2</sub>, ..., *s*<sub class="lower-index">*k*</sub> is called beautiful, if the concatenation of these strings is string *q* (formally, *s*<sub class="lower-index">1</sub> + *s*<sub class="lower-index">2</sub> + ... + *s*<sub class="lower-index">*k*</sub> = *q*) and the first characters of these strings are distinct.

Find any beautiful sequence of strings or determine that the beautiful sequence doesn't exist.
The first line contains a positive integer *k* (1 ≤ *k* ≤ 26) — the number of strings that should be in a beautiful sequence. 

The second line contains string *q*, consisting of lowercase Latin letters. The length of the string is within range from 1 to 100, inclusive.
x = int(input())
st = input()

s = set(list(st))
if len(s) < x:
    print("NO")
    exit()


lal = []
for ch in st:
    if ch in s and x > 1:
        if len(lal) != 0:
            print("".join(lal))
            x -= 1
        lal.clear()
        s.remove(ch)
    lal.append(ch)

print("".join(lal))