import sys
input = sys.stdin.readline

def f(T):
    acc = [1]*(N+1)
    
    for Ti in T:
        nacc = [0]
        
        for i in range(N):
            v = acc[i] if S[i]==Ti else 0
            nacc.append((nacc[-1]+v)%MOD)
        
        acc = nacc
    
    return sum(acc)%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)