import java.io.*;
import java.util.*;

class Main
{
    public static void main(String args[])throws Exception
    {
        BufferedReader bu=new BufferedReader(new InputStreamReader(System.in));
        StringBuilder sb=new StringBuilder();
        int n=Integer.parseInt(bu.readLine());
        char s[]=bu.readLine().toCharArray();
        HashMap<Character,Integer> mp=new HashMap<>();
        String x="yukicoder";
        int i,l=x.length();
        for(i=0;i<l;i++) mp.put(x.charAt(i),i);
        mp.put('?',l);

        long dp[]=new long[l],M=(int)1e9+7;
        for(i=0;i<n;i++)
        if(mp.get(s[i])!=null)
        {
            int in=mp.get(s[i]);
            if(in==0) dp[0]=(dp[0]+1)%M;
            else if(in!=l) dp[in]=(dp[in]+dp[in-1])%M;
            else
            {
                for(int j=l-1;j>0;j--) dp[j]=(dp[j-1]+dp[j])%M;
                dp[0]=(dp[0]+1)%M;
            }
        }
        System.out.println(dp[l-1]);
    }
}