n = int(input())
s = input()
memo = {
    "A": 0,
    "B": 0,
    "C": 0,
    "D": 0,
    "E": 0,
    "F": 0,
    "G": 0,
    "H": 0,
    "I": 0,
    "J": 0,
    "K": 0,
    "L": 0,
    "M": 0,
    "N": 0,
    "O": 0,
    "P": 0,
    "Q": 0,
    "R": 0,
    "S": 0,
    "T": 0,
    "U": 0,
    "V": 0,
    "W": 0,
    "X": 0,
    "Y": 0,
    "Z": 0,
}
for i in range(n):
    memo[s[i]] += 1
v = memo.values()
for s in v:
    print(s, end="")