import io
import sys

sys.stdin = io.StringIO('''1
aabbccc''')  # cabcacb

from collections import Counter


def reorganizeString(str):
    cnt = Counter(str)
    # 桶的数目等于字符串中最多的元素的数目
    bucketNum = cnt.most_common(1)[0][1]
    buckets = [[] for _ in range(bucketNum)]
    idx = 0
    # 优先填充数目最多的元素
    for c, num in cnt.most_common():
        while num:
            buckets[idx].append(c)
            # 循环在不同桶中进行填充
            idx = (idx + 1) % bucketNum
            num -= 1
    return "".join(["".join(bucket) for bucket in buckets]) if list(map(len, buckets)).count(1) <= 1 else ""


n = int(input())
str = input()
result = reorganizeString(str)
if result == '':
    print('no')
else:
    print('yes')
    print(result)