ans = 0
n = int(input())
s = input()
ans = 0
def main(s, t):
	global ans
	n = len(s)
	t = list(t)
	dp = [[0] * (len(t) + 1) for i in range(n + 1)]
	dp[0][0] = 1
	mod = 10 ** 9 + 7
	for i in range(n):
		try:
			ind = t.index(s[i])
		except: ind = len(t) + 1
		for j in range(len(t) + 1):
			dp[i + 1][j] += dp[i][j]
			if j == ind: dp[i + 1][j + 1] += dp[i][j]; dp[i + 1][j + 1] %= mod
			dp[i + 1][j] %= mod
	ans += dp[-1][-1]
ts = ["yukicoder", "?ukicoder", "y?kicoder", "yu?icoder", "yuk?coder", "yuki?oder", "yukic?der", "yukico?er", "yukicod?r", "yukicode?"]
for t in ts:
	main(s, t)
print(ans % (10 ** 9 + 7))