Buggy python submission (verdict: Time Limit Exceeded):
from collections import defaultdict
import itertools
from functools import reduce


def analyze(string):
  s_count = defaultdict(int)
  for s in string:
    s_count[s] += 1
  counts = list(s_count.values())
  return counts

def count(counts, num_set):
    if num_set == 1:
        return sum(counts)
    if num_set == 2:
        num_sum = sum(counts)
        ans = 0
        for i in range(len(counts)):
            num_sum -= counts[i]
            ans += counts[i] * num_sum
        return ans

    ans = 0
    for i in range(len(counts) - 1):
        ans += counts[i] * count(counts[i + 1:], num_set - 1)
    return ans

N = int(input())
string = input()

counts = analyze(string)
ans = 0
for i in range(1, len(counts) + 1):
    ans += count(counts, i)
print(ans % (10**9 + 7))


Fixed submission:
from collections import defaultdict
import itertools
from functools import reduce


def analyze(string):
  s_count = defaultdict(int)
  for s in string:
    s_count[s] += 1
  counts = tuple(s_count.values())
  return counts

N = int(input())
string = input()

def search(N, string):
    memo = {}
    def count(counts, num_set):
        if (counts, num_set) in memo:
            return memo[(counts, num_set)]

        if num_set == 1:
            ans = sum(counts)
        elif num_set == 2:
            num_sum = sum(counts)
            ans = 0
            for i in range(len(counts)):
                num_sum -= counts[i]
                ans += counts[i] * num_sum
        else:
            ans = 0
            for i in range(len(counts) - 1):
                ans += counts[i] * count(counts[i + 1:], num_set - 1)

        memo[(counts, num_set)] = ans
        return ans

    counts = analyze(string)
    ans = 0
    for i in range(1, len(counts) + 1):
        ans += count(counts, i)
    print(ans % (10**9 + 7))

search(N, string)

Buggy python submission (verdict: Time Limit Exceeded):
from collections import defaultdict
import itertools
from functools import reduce


def analyze(string):
  s_count = defaultdict(int)
  for s in string:
    s_count[s] += 1
  return s_count

def count_up(s_count):
  strings = list(s_count.keys())
  ans = 0
  for num in range(1, len(strings) + 1):
    for s_list in itertools.combinations(strings, num):
      num_list = [s_count[s] for s in s_list]
      ans += reduce((lambda x, y: x * y), num_list)
  print(ans % (10**9 + 7))

N = int(input())
string = input()

s_count = analyze(string)
count_up(s_count)


Fixed submission:
from collections import defaultdict
import itertools
from functools import reduce


def analyze(string):
  s_count = defaultdict(int)
  for s in string:
    s_count[s] += 1
  counts = tuple(s_count.values())
  return counts

N = int(input())
string = input()

def search(N, string):
    memo = {}
    def count(counts, num_set):
        if (counts, num_set) in memo:
            return memo[(counts, num_set)]

        if num_set == 1:
            ans = sum(counts)
        elif num_set == 2:
            num_sum = sum(counts)
            ans = 0
            for i in range(len(counts)):
                num_sum -= counts[i]
                ans += counts[i] * num_sum
        else:
            ans = 0
            for i in range(len(counts) - 1):
                ans += counts[i] * count(counts[i + 1:], num_set - 1)

        memo[(counts, num_set)] = ans
        return ans

    counts = analyze(string)
    ans = 0
    for i in range(1, len(counts) + 1):
        ans += count(counts, i)
    print(ans % (10**9 + 7))

search(N, string)

Buggy python submission (verdict: Runtime Error):
from collections import defaultdict
import itertools


def analyze(string):
  s_count = defaultdict(int)
  for s in string:
    s_count[s] += 1
  return s_count

def count_up(s_count):
  strings = list(s_count.keys())
  ans = 0
  for num in range(1, len(strings) + 1):
    for s_list in itertools.combinations(strings, num):
      num_list = [s_count[s] for s in s_list]
      ans += reduce((lambda x, y: x * y), num_list)
  print(ans % (10**9 + 7))

N = int(input())
string = input()

s_count = analyze(string)
count_up(s_count)


Fixed submission:
from collections import defaultdict
import itertools
from functools import reduce


def analyze(string):
  s_count = defaultdict(int)
  for s in string:
    s_count[s] += 1
  counts = tuple(s_count.values())
  return counts

N = int(input())
string = input()

def search(N, string):
    memo = {}
    def count(counts, num_set):
        if (counts, num_set) in memo:
            return memo[(counts, num_set)]

        if num_set == 1:
            ans = sum(counts)
        elif num_set == 2:
            num_sum = sum(counts)
            ans = 0
            for i in range(len(counts)):
                num_sum -= counts[i]
                ans += counts[i] * num_sum
        else:
            ans = 0
            for i in range(len(counts) - 1):
                ans += counts[i] * count(counts[i + 1:], num_set - 1)

        memo[(counts, num_set)] = ans
        return ans

    counts = analyze(string)
    ans = 0
    for i in range(1, len(counts) + 1):
        ans += count(counts, i)
    print(ans % (10**9 + 7))

search(N, string)

Buggy python submission (verdict: Time Limit Exceeded):
from collections import defaultdict
import itertools


def analyze(string):
  s_count = defaultdict(int)
  for s in string:
    s_count[s] += 1
  return s_count

def count_up(s_count):
  strings = list(s_count.keys())
  ans = 0
  for num in range(1, len(strings) + 1):
    for s_list in itertools.combinations(strings, num):
      a = 1
      for s in s_list:
        a *= s_count[s]
      ans += a
  print(ans % (10**9 + 7))

N = int(input())
string = input()

s_count = analyze(string)
count_up(s_count)


Fixed submission:
from collections import defaultdict
import itertools
from functools import reduce


def analyze(string):
  s_count = defaultdict(int)
  for s in string:
    s_count[s] += 1
  counts = tuple(s_count.values())
  return counts

N = int(input())
string = input()

def search(N, string):
    memo = {}
    def count(counts, num_set):
        if (counts, num_set) in memo:
            return memo[(counts, num_set)]

        if num_set == 1:
            ans = sum(counts)
        elif num_set == 2:
            num_sum = sum(counts)
            ans = 0
            for i in range(len(counts)):
                num_sum -= counts[i]
                ans += counts[i] * num_sum
        else:
            ans = 0
            for i in range(len(counts) - 1):
                ans += counts[i] * count(counts[i + 1:], num_set - 1)

        memo[(counts, num_set)] = ans
        return ans

    counts = analyze(string)
    ans = 0
    for i in range(1, len(counts) + 1):
        ans += count(counts, i)
    print(ans % (10**9 + 7))

search(N, string)

Buggy python submission (verdict: Runtime Error):
from collections import defaultdict
import itertools
 

def analyze(string):
  s_count = defaultdict(int)
  for s in string:
    s_count[s] += 1
  return s_count
 
def count_up(s_count):
  strings = list(s_count.keys())
  ans = 0
  for num in range(1, len(strings) + 1):
    for s_list in itertools.product(strings, num):
      a = 1
      for s in s_list:
        a *= s_count[s]
      ans += a
  print(ans)
  
N, string = input().split('\n')
N = int(N)
 
s_count = analyze(string)
count_up(s_count)

Fixed submission:
from collections import defaultdict
import itertools
from functools import reduce


def analyze(string):
  s_count = defaultdict(int)
  for s in string:
    s_count[s] += 1
  counts = tuple(s_count.values())
  return counts

N = int(input())
string = input()

def search(N, string):
    memo = {}
    def count(counts, num_set):
        if (counts, num_set) in memo:
            return memo[(counts, num_set)]

        if num_set == 1:
            ans = sum(counts)
        elif num_set == 2:
            num_sum = sum(counts)
            ans = 0
            for i in range(len(counts)):
                num_sum -= counts[i]
                ans += counts[i] * num_sum
        else:
            ans = 0
            for i in range(len(counts) - 1):
                ans += counts[i] * count(counts[i + 1:], num_set - 1)

        memo[(counts, num_set)] = ans
        return ans

    counts = analyze(string)
    ans = 0
    for i in range(1, len(counts) + 1):
        ans += count(counts, i)
    print(ans % (10**9 + 7))

search(N, string)

Buggy python submission (verdict: Runtime Error):
from collections import defaultdict
import itertools


def analyze(string):
  s_count = defaultdict(int)
  for s in string:
    s_count[s] += 1
  return s_count

def count_up(s_count):
  strings = list(s_count.keys())
  ans = 0
  for num in range(1, len(strings) + 1):
    for s_list in itertools.product(strings, num):
      a = 1
      for s in s_list:
        a *= s_count[s]
      ans += a
  print(ans)
  
N, string = input().split('\n')
N = int(N)

s_count = analyze(string)
count_up(s_count)

Fixed submission:
from collections import defaultdict
import itertools
from functools import reduce


def analyze(string):
  s_count = defaultdict(int)
  for s in string:
    s_count[s] += 1
  counts = tuple(s_count.values())
  return counts

N = int(input())
string = input()

def search(N, string):
    memo = {}
    def count(counts, num_set):
        if (counts, num_set) in memo:
            return memo[(counts, num_set)]

        if num_set == 1:
            ans = sum(counts)
        elif num_set == 2:
            num_sum = sum(counts)
            ans = 0
            for i in range(len(counts)):
                num_sum -= counts[i]
                ans += counts[i] * num_sum
        else:
            ans = 0
            for i in range(len(counts) - 1):
                ans += counts[i] * count(counts[i + 1:], num_set - 1)

        memo[(counts, num_set)] = ans
        return ans

    counts = analyze(string)
    ans = 0
    for i in range(1, len(counts) + 1):
        ans += count(counts, i)
    print(ans % (10**9 + 7))

search(N, string)