source_code: import java.io.OutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.PrintWriter;
  import java.util.InputMismatchException;
  import java.io.IOException;
  import java.io.InputStream;
  
  /**
   * Built using CHelper plug-in
   * Actual solution is at the top
   *
   * @author pandusonu
   */
  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 int mod = (int) Math.pow(10, 9) + 7;
  
          public void solve(int testNumber, InputReader in, PrintWriter out) {
              // out.print("Case #" + testNumber + ": ");
              int n = in.readInt();
              int[] a = new int[n];
              for (int i = 0; i < n; i++) {
                  a[i] = in.readString().charAt(0) == 'f' ? 1 : 0;
              }
              long[][] ans = new long[n][n + 2];
              ans[0][0] = 1;
              int indent = 0;
              if (a[0] == 1) indent++;
              for (int i = 1; i < n; i++) {
                  if (a[i - 1] == 1) {
                      for (int j = indent - 1; j >= 1; j--) {
                          ans[i][j] = ans[i - 1][j - 1];
                      }
                      ans[i][indent] = 1;
                  } else {
                      for (int j = indent; j >= 0; j--) {
                          ans[i][j] = (ans[i][j + 1] + ans[i - 1][j]) % mod;
                      }
                  }
                  indent += a[i];
              }/*
          for (int i = 0; i < n; i++) {
              for (int j = 0; j < n; j++) {
                  out.print(ans[i][j]+" ");
              }
              out.println();
          }*/
              long aa = 0;
              for (int i = 0; i < n + 2; i++) {
                  aa = (aa + ans[n - 1][i]) % mod;
              }
              out.println(aa);
          }
  
      }
  
      static class InputReader {
          private final InputStream stream;
          private final byte[] buf = new byte[1024];
          private int curChar;
          private int numChars;
  
          public InputReader(InputStream stream) {
              this.stream = stream;
          }
  
          private int read() {
              try {
                  if (curChar >= numChars) {
                      curChar = 0;
                      numChars = stream.read(buf);
                      if (numChars <= 0)
                          return -1;
                  }
              } catch (IOException e) {
                  throw new RuntimeException(e);
              }
              return buf[curChar++];
          }
  
          public int readInt() {
              return (int) readLong();
          }
  
          public long readLong() {
              int c = read();
              while (isSpaceChar(c)) {
                  c = read();
                  if (c == -1) throw new RuntimeException();
              }
              boolean negative = false;
              if (c == '-') {
                  negative = true;
                  c = read();
              }
              long res = 0;
              do {
                  if (c < '0' || c > '9') throw new InputMismatchException();
                  res *= 10;
                  res += (c - '0');
                  c = read();
              } while (!isSpaceChar(c));
              return negative ? (-res) : (res);
          }
  
          public String readString() {
              int c = read();
              while (isSpaceChar(c)) c = read();
              StringBuilder res = new StringBuilder();
              do {
                  res.append((char) c);
                  c = read();
              } while (!isSpaceChar(c));
              return res.toString();
          }
  
          private boolean isSpaceChar(int c) {
              return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
          }
  
      }
  }
  
  