source_code: import java.util.Scanner;
  
  public class Solution {
  		
  	public static void main(String[] args) {
  		// Write your code here
        Scanner s=new Scanner(System.in);
  	  int n=s.nextInt();
  	  char[] seq=new char[n];
  	  for(int i=0;i<n;i++){
  		  seq[i]=s.next().charAt(0);  
  	  }
  	  long mod=(long)Math.pow(10,9)+7;
  	  long[][] arr=new long[n][n];
  	  arr[0][0]=1;
  	  for(int i=1;i<n;i++){
  		  if(seq[i-1]=='f'){
  			  for(int j=1;j<n;j++){
  				  arr[i][j]=arr[i-1][j-1];
  			  }
  		  }else{
  			  long sum=0;
  			  for(int j=n-1;j>=0;j--){
  				  sum=(sum+arr[i-1][j])%mod;
  				  arr[i][j]=sum;
  			  }
  		  }
  	  }
  	  long ans=0;
  	  for(int i=0;i<n;i++){
  		  ans=(ans+arr[n-1][i])%mod;
  	  }
  	  System.out.println(ans);
  	}
  }