source_code: import java.io.OutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.PrintWriter;
  import java.util.Arrays;
  import java.util.InputMismatchException;
  import java.io.IOException;
  import java.io.InputStream;
  
  /**
   * Built using CHelper plug-in
   * Actual solution is at the top
   *
   * @author ankur
   */
  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 {
          String[] str;
          long mod = (long) 1e9 + 7;
          long[][] dp;
  
          public void solve(int testNumber, InputReader in, PrintWriter out) {
              int n = in.nextInt();
              str = new String[n];
              dp = new long[n + 2][n + 2];
              for (int i = 0; i < dp.length; i++) {
                  Arrays.fill(dp[i], -1);
              }
              for (int i = 0; i < n; i++) {
                  str[i] = in.readString();
              }
              if (str[0].charAt(0) == 'f') {
                  out.print(solve(1, 1));
              } else {
                  out.print(solve(1, 0));
              }
          }
  
          long solve(int n, int horiz) {
              if (horiz < 0)
                  return 0;
              if (n >= str.length - 1) {
                  return 1;
              }
              if (dp[n][horiz] != -1) {
                  return dp[n][horiz];
              }
              if (str[n].charAt(0) == 'f') {
                  return dp[n][horiz] = solve(n + 1, horiz + 1);
              } else {
                  long ans1 = solve(n, horiz - 1);
                  //System.out.println(ans1+" "+n+" egsvd"+horiz);
                  ans1 += solve(n + 1, horiz);
                  //System.out.println(ans1+" "+n+" "+horiz);
                  ans1 = ans1 % mod;
                  return dp[n][horiz] = ans1;
              }
          }
  
      }
  
      static class InputReader {
          private final InputStream stream;
          private final byte[] buf = new byte[8192];
          private int curChar;
          private int snumChars;
  
          public InputReader(InputStream st) {
              this.stream = st;
          }
  
          public int read() {
              //*-*------clare------
  
              if (snumChars == -1)
                  throw new InputMismatchException();
              if (curChar >= snumChars) {
                  curChar = 0;
                  try {
                      snumChars = stream.read(buf);
                  } catch (IOException e) {
                      throw new InputMismatchException();
                  }
                  if (snumChars <= 0)
                      return -1;
              }
              return buf[curChar++];
          }
  
          public int nextInt() {
              int c = read();
              while (isSpaceChar(c)) {
                  c = read();
              }
              int sgn = 1;
              if (c == '-') {
                  sgn = -1;
                  c = read();
              }
              int res = 0;
              do {
                  res *= 10;
                  res += c - '0';
                  c = read();
              } while (!isSpaceChar(c));
              return res * sgn;
          }
  
          public String readString() {
              int c = read();
              while (isSpaceChar(c)) {
                  c = read();
              }
              StringBuilder res = new StringBuilder();
              do {
                  res.appendCodePoint(c);
                  c = read();
              } while (!isSpaceChar(c));
              return res.toString();
          }
  
          public boolean isSpaceChar(int c) {
              return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
          }
  
      }
  }
  
  