Калькулятор с восствновлением ответа

n = int(input())
L = [0] * (n + 1)
for i in range(2, n + 1):
    L[i] = L[i - 1]
    if i % 2 == 0 and L[i // 2] < L[i]:
        L[i] = L[i // 2]
    if i % 3 == 0 and L[i // 3] < L[i]:
        L[i] = L[i // 3]
    L[i] += 1   

ans = ''
i = n
while i > 1:
    if L[i - 1] == L[i] - 1:
        i -= 1
        ans += '1'
    elif i % 2 == 0 and L[i // 2] == L[i] - 1:
        i //= 2
        ans += '2'
    else:
        i //= 3
        ans += '3'
print(ans[::-1])

Граф, но не Монте-Кисто

n, m = map(int, input().split())
L = [[i] for i in range(n)]
for  i in range(m):
    a, b = input().split()
    a = ord(a) - 65
    b = ord(b) - 65
    L[a].append(b)
dp = [0 for i in range(n)]
dp[0] = 1
for i in range(n):
    for j in range(1, len(L[i])):
        dp[L[i][j]] += dp[i]
print(dp[-1])