a = list(" yukicoder")
aa = list(" yukicoder")
n = int(input())
s = list(input())
ans = 0
for i in range(10):
    dp = [[0] * (n+1)] +  [[0] * (n+1) for _ in range(9)]
    dp[0][0] = 1
    for j in range(10):
        for k in range(1,n+ 1):
            dp[j][k] += dp[j][k-1]
            if s[k-1] == a[j]:
                dp[j][k] += dp[j-1][k-1]
    ans += dp[-1][-1]
    if i == 9:break
    a[i+1] = "?"
    a[i] = aa[i]
#     print(dp[-1])
print(ans)