#!/usr/bin/python3 import bisect import collections import heapq import itertools import math import os import sys def main(): n = read_int() S = inp() A = [0] * 26 for ch in S: A[ord(ch) - ord('A')] += 1 ans = [] for a in A: ans.append(str(a)) print(''.join(ans)) ############################################################################### DEBUG = 'DEBUG' in os.environ def inp(): return sys.stdin.readline().rstrip() def read_int(): return int(inp()) def read_ints(): return [int(e) for e in inp().split()] def list2d(d1, d2, init=None): return [[init] * d2 for _ in range(d1)] def list3d(d1, d2, d3, init=None): return [[[init] * d3 for _ in range(d2)] for _ in range(d1)] def list4d(d1, d2, d3, d4, init=None): return [[[[init] * d4 for _ in range(d3)] for _ in range(d2)] for _ in range(d1)] def debug(fmt, *args): if DEBUG: if args: print(fmt.format(*args), file=sys.stderr) else: print(fmt, file=sys.stderr) if __name__ == '__main__': main()