import sys
input = sys.stdin.readline

def f(T):
    dp = [[0]*N for _ in range(len(T))]
    
    for i in range(N):
        if S[i]==T[0]:
            dp[0][i] = 1
    
    for i in range(1, len(T)):
        acc = [0]
        
        for j in range(N):
            acc.append((acc[-1]+dp[i-1][j])%MOD)
        
        for j in range(N):
            if S[j]==T[i]:
                dp[i][j] = acc[j]
    
    return sum(dp[-1])%MOD
    
N = int(input())
S = input()[:-1]
MOD = 10**9+7
T = 'yukicoder'
ans = f(T)

for i in range(len(T)):
    ans += f(T[:i]+'?'+T[i+1:])
    ans %= MOD

print(ans)