source_code: import java.util.Scanner;
  public class maestro{
      public static void main(String[] args){
          Scanner sc = new Scanner(System.in);
          int N = sc.nextInt();
          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++){
              char c = sc.next().charAt(0);
              if (c=='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);
      }
  }