source_code: import java.util.*;
  
  public class HelloWorld{
  
       public static void main(String []args){
          final long MOD = 1000000007;
          Scanner scan = new Scanner(System.in);
          int now = 1;
          int maxStatements = scan.nextInt();
          long[] dp = new long[maxStatements + 1];
          dp[now] = 1;
          while(maxStatements > 0)
          {
              String add = scan.next();
              if (add.equals("f"))
              {
                  now++;
              }
              else
              {
                  for (int k = 1; k <= now; k++)
                  {
                      dp[k] = ((dp[k] + dp[k-1]) % MOD);
                  }
              }
              maxStatements--;
          }
          System.out.println(dp[now]);
       }
  }