N = int(input())
S = input()
dp = [1] + [0] * 9
dic = dict(zip("yukicoder",range(1,N+1)))
for s in S:
    if s in dic:
        a = dic[s]
        dp[a] += dp[a-1]
    if s  == "?":
        for i in reversed(range(1,10)):
            dp[i] += dp[i-1]
print(dp[-1])