source_code: import java.io.OutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.PrintWriter;
  import java.util.*;
  import java.io.BufferedReader;
  import java.io.InputStreamReader;
  
  
  public class Main {
      public static void main(String[] args) {
          InputStream inputStream = System.in;
          OutputStream outputStream = System.out;
          TaskC.InputReader in = new TaskC.InputReader(inputStream);
          PrintWriter out = new PrintWriter(outputStream);
          TaskC solver = new TaskC();
          solver.Solve(in, out);
          out.close();
      }
  
  
      static class TaskC {
  
          private long mod = 1_000_000_007;
          private int n;
          private boolean[] s;
  
          public void Solve(InputReader in, PrintWriter out) {
              n = in.NextInt();
              s = new boolean[n];
              for (int i = 0; i < n; i++) {
                  String ss = in.Next();
                  s[i] = ss.charAt(0) == 'f';
              }
              if (s[n - 1]) {
                  out.println(0);
                  return;
              }
              long[] dpSum = new long[n + 1], lastDpSum = new long[n + 1];
              for (int i = 0; i <= n; i++) {
                  lastDpSum[i] = i + 1;
              }
              for (int i = n - 2; i >= 0; i--) {
                  for (int j = 0; j <= i; j++) {
                      if (!s[i]) {
                          dpSum[j] = lastDpSum[j];
                      } else {
                          dpSum[j] = lastDpSum[j + 1] - lastDpSum[j];
                      }
                      if (j != 0) {
                          dpSum[j] += dpSum[j - 1];
                      }
                      dpSum[j] %= mod;
                      while (dpSum[j] < 0) dpSum[j] += mod;
  
                  }
                  long[] temp = dpSum;
                  dpSum = lastDpSum;
                  lastDpSum = temp;
              }
              out.println(lastDpSum[0]);
          }
  
          public static int GetMax(int[] ar) {
              int max = Integer.MIN_VALUE;
              for (int a : ar) {
                  max = Math.max(max, a);
              }
              return max;
          }
  
          public static int GetMin(int[] ar) {
              int min = Integer.MAX_VALUE;
              for (int a : ar) {
                  min = Math.min(min, a);
              }
              return min;
          }
  
          public static long GetSum(int[] ar) {
              long s = 0;
              for (int a : ar) s += a;
              return s;
          }
  
          public static int[] GetCount(int[] ar) {
              return GetCount(ar, GetMax(ar));
          }
  
          public static int[] GetCount(int[] ar, int maxValue) {
              int[] dp = new int[maxValue + 1];
              for (int a : ar) {
                  dp[a]++;
              }
              return dp;
          }
  
          static class InputReader {
              public BufferedReader reader;
              public StringTokenizer tokenizer;
  
              public InputReader(InputStream stream) {
                  reader = new BufferedReader(new InputStreamReader(stream), 32768);
                  tokenizer = null;
              }
  
              public String Next() {
                  while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                      try {
                          tokenizer = new StringTokenizer(reader.readLine(), " \t\n\r\f,");
                      } catch (IOException e) {
                          throw new RuntimeException(e);
                      }
                  }
                  return tokenizer.nextToken();
              }
  
              public int NextInt() {
                  return Integer.parseInt(Next());
              }
  
              public long NextLong() {
                  return Long.parseLong(Next());
              }
  
              public double NextDouble() {
                  return Double.parseDouble(Next());
              }
  
              public int[] NextIntArray(int n) {
                  return NextIntArray(n, 0);
              }
  
              public int[] NextIntArray(int n, int offset) {
                  int[] a = new int[n];
                  for (int i = 0; i < n; i++) {
                      a[i] = NextInt() - offset;
                  }
                  return a;
              }
  
              public int[][] NextIntMatrix(int n, int m) {
                  return NextIntMatrix(n, m, 0);
              }
  
              public int[][] NextIntMatrix(int n, int m, int offset) {
                  int[][] a = new int[n][m];
                  for (int i = 0; i < n; i++) {
                      for (int j = 0; j < m; j++) {
                          a[i][j] = NextInt() - offset;
                      }
                  }
                  return a;
              }
          }
      }
  }
  