Buggy python submission (verdict: Runtime Error):
#import sys
#input = sys.stdin.readline
import random
import bisect
import collections
import itertools
import operator
#from statistics import mean, median, variance, stdev




#template input

def IT(): #整数1個
    return int(input())
def IL(): #整数複数
    return [int(_) for _ in input().split()]
def IS(): #文字列複数
    return [_ for _ in input().split()]
def ILS(n): #整数1つ　縦にズラーってなってるやつ
    return [int(input()) for _ in range(n)]
def SLS(n): #文字列　縦にズラーってなってるやつ
    return [input() for _ in range(n)]
def ILSS(n): #整数複数　縦にズラーってなってるやつ
    return [[int(_) for _ in input().split()] for j in range(n)]

#template technique
def bit_full_search(ss):
    n = len(ss)
    for i in range(1 << n):
        s = ""
        for j in range(n + 1):
            if ((1 & i >> j) == 1):
                s += ss[j]
        print(s)
def bit_full_search2(A):
    #https://blog.rossywhite.com/2018/08/06/bit-search/
    value = []
    for i in range(1 << len(A)):
        output = []

        for j in range(len(A)):
            if ((i >> j) & 1) == 1:
                #output.append(A[j])
                output.append(A[j])
        value.append([format(i, 'b').zfill(16), sum(output)])

    value.sort(key=lambda x:x[1])
    bin = [value[k][0] for k in range(len(value))]
    val = [value[k][1] for k in range(len(value))]
    return bin, val
def matching_bisect(list1_val, list2_val, n):
    #2分探索
    j = 0
    for i in range(len(list1_val)):
        j = bisect.bisect_left(list2_val, n - list1_val[i])
        if j < len(list2_val):
            if list1_val[i] + list2_val[j] == n:
                #ans = list2_bin[j] + list1_bin[i]
                break
    return j


class UnionFind:
    def __init__(self, elems=None):
        class KeyDict(dict):
            def __missing__(self, key):
                self[key] = key
                return key

        self.parent = KeyDict()
        self.rank = collections.defaultdict(int)

        if elems is not None:
            for elem in elems:
                _, _ = self.parent[elem], self.rank[elem]

    def find(self, x):
        if self.parent[x] == x:
            return x
        else:
            self.parent[x] = self.find(self.parent[x])
            return self.parent[x]

    def unite(self, x, y):
        x = self.find(x)
        y = self.find(y)
        if self.rank[x] < self.rank[y]:
            self.parent[x] = y
        else:
            self.parent[y] = x
        if self.rank[x] == self.rank[y]:
            self.rank[x] += 1

    def are_same(self, x, y):
        return self.find(x) == self.find(y)

    def grouper(self):
        roots = [(x, self.find(x_par)) for x, x_par in self.parent.items()]
        root = operator.itemgetter(1)
        for _, group in itertools.groupby(sorted(roots, key=root), root):
            yield [x for x, _ in group]
















"""ここからメインコード"""


def main():
    n=int(input())
    s=input()
    alp = [0 for i in range(26)]
    for i in range(n):
        alp[ord(s[i])-97] += 1
    ans = 1
    for i in range(n):
        ans *= alp[i]+1


    print(ans-1)





main()







Fixed submission:
def main():
    mod = 10 **9 +7
    n=int(input())
    s=input()
    alp = [0 for i in range(26)]
    for i in range(n):
        alp[ord(s[i])-97] += 1
    ans = 1
    for i in range(26):
        ans *= (alp[i]+1)


    print((ans-1)%mod)

main()