source_code: 
  import java.io.OutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.PrintWriter;
  import java.io.PrintStream;
  import java.util.StringTokenizer;
  import java.io.IOException;
  import java.io.BufferedReader;
  import java.io.InputStreamReader;
  import java.io.InputStream;
  
  /**
   * Built using CHelper plug-in
   * Actual solution is at the top
   *
   * @author Wolfgang Beyer
   */
  public class Main {
      public static void main(String[] args) {
          InputStream inputStream = System.in;
          OutputStream outputStream = System.out;
          InputReader in = new InputReader(inputStream);
          PrintWriter out = new PrintWriter(outputStream);
          TaskC solver = new TaskC();
          solver.solve(1, in, out);
          out.close();
      }
  
      static class TaskC {
          public void solve(int testNumber, InputReader in, PrintWriter out) {
              int n = in.nextInt();
              long MOD = 1000000007;
  
              long[] current = new long[n + 3];
              //long[] sum = new long[n + 3];
              current[0] = 1;
  
              for (int i = 0; i < n - 1; i++) {
  
                  String s = in.next();
                  if (s.equals("f")) {
                      for (int j = i + 1; j > 0; j--) {
                          current[j] = current[j - 1];
                          current[j] %= MOD;
                      }
                      current[0] = 0;
                  } else {
                      for (int j = i + 1; j >= 0; j--) {
                          //sum[j] = sum[j + 1] + current[j];
                          current[j] = current[j + 1] + current[j];
                          current[j] %= MOD;
                      }
                      //for (int j = 0; j <= i + 1; j++) {
                      //  current[j] =
                      //}
                  }
              }
              long result = 0;
              for (int i = 0; i <= n; i++) {
                  result += current[i];
                  result %= MOD;
              }
              out.println(result);
          }
  
      }
  
      static class InputReader {
          private static BufferedReader in;
          private static StringTokenizer tok;
  
          public InputReader(InputStream in) {
              this.in = new BufferedReader(new InputStreamReader(in));
          }
  
          public int nextInt() {
              return Integer.parseInt(next());
          }
  
          public String next() {
              try {
                  while (tok == null || !tok.hasMoreTokens()) {
                      tok = new StringTokenizer(in.readLine());
                      //tok = new StringTokenizer(in.readLine(), ", \t\n\r\f"); //adds commas as delimeter
                  }
              } catch (IOException ex) {
                  System.err.println("An IOException was caught :" + ex.getMessage());
              }
              return tok.nextToken();
          }
  
      }
  }
  
  