n=int(input())
s=input()
t="yukicoder"
m=len(t)
M=10**9+7
q=[0]*m
for c in s:
  for i in reversed(range(1,m)):
    if c==t[i] or c=="?":
      q[i]+=q[i-1]
      q[i]%=M
  if c==t[0] or c=="?":
    q[0]+=1
print(q[-1])