source_code: import java.io.OutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.io.PrintWriter;
  import java.io.BufferedWriter;
  import java.io.IOException;
  import java.io.InputStreamReader;
  import java.util.StringTokenizer;
  import java.io.Writer;
  import java.io.OutputStreamWriter;
  import java.io.BufferedReader;
  import java.io.InputStream;
  
  /**
   * Built using CHelper plug-in
   * Actual solution is at the top
   *
   * @author phantom11
   */
  public class Main {
      public static void main(String[] args) {
          InputStream inputStream = System.in;
          OutputStream outputStream = System.out;
          InputReader in = new InputReader(inputStream);
          OutputWriter out = new OutputWriter(outputStream);
          TaskC solver = new TaskC();
          solver.solve(1, in, out);
          out.close();
      }
  
      static class TaskC {
          long MOD = (long) 1e9 + 7;
          long[][] dp;
          int[] a;
  
          public void solve(int testNumber, InputReader in, OutputWriter out) {
              int N = in.nextInt();
              a = new int[N];
              dp = new long[N][N];
              int i;
              for (i = 0; i < N; i++) {
                  char c = in.nextChar();
                  if (c == 'f') {
                      a[i] = 1;
                  }
              }
  
              out.printLine(iterative());
  //        for(i=0;i<=N;i++) {
  //            Arrays.fill(dp[i], -1);
  //        }
  //        out.printLine(recur(0, 0));
          }
  
          public long iterative() {
              int i, j, N = a.length, lastLevel = 0;
              dp[0][0] = 1;
              for (i = 1; i < N; i++) {
                  if (a[i - 1] == 1) {
                      lastLevel++;
                      for (j = 1; j <= lastLevel; j++) {
                          dp[i][j] = dp[i - 1][j - 1];
                      }
                  } else {
                      dp[i][N - 1] = dp[i - 1][N - 1];
                      for (j = N - 2; j >= 0; j--) {
                          dp[i][j] = (dp[i][j + 1] + dp[i - 1][j]) % MOD;
                      }
                  }
              }
              long ans = 0;
              for (i = 0; i < N; i++) {
                  ans += dp[N - 1][i];
              }
              return ans % MOD;
          }
  
      }
  
      static class InputReader {
          BufferedReader in;
          StringTokenizer tokenizer = null;
  
          public InputReader(InputStream inputStream) {
              in = new BufferedReader(new InputStreamReader(inputStream));
          }
  
          public String next() {
              try {
                  while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                      tokenizer = new StringTokenizer(in.readLine());
                  }
                  return tokenizer.nextToken();
              } catch (IOException e) {
                  return null;
              }
          }
  
          public int nextInt() {
              return Integer.parseInt(next());
          }
  
          public char nextChar() {
              return next().charAt(0);
          }
  
      }
  
      static class OutputWriter {
          private final PrintWriter writer;
  
          public OutputWriter(OutputStream outputStream) {
              writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
          }
  
          public OutputWriter(Writer writer) {
              this.writer = new PrintWriter(writer);
          }
  
          public void print(Object... objects) {
              for (int i = 0; i < objects.length; i++) {
                  if (i != 0)
                      writer.print(' ');
                  writer.print(objects[i]);
              }
          }
  
          public void printLine(Object... objects) {
              print(objects);
              writer.println();
          }
  
          public void close() {
              writer.close();
          }
  
      }
  }
  
  