source_code: import java.lang.Math;
  import java.io.*;    
  import java.util.*;
   
  public class Main {
          
          static BufferedReader in;
          static PrintStream out;
          static StringTokenizer tok;
          
          @SuppressWarnings("empty-statement")
  	public static void main(String[] args) throws NumberFormatException, IOException, Exception {
              in = new BufferedReader(new InputStreamReader(System.in));
              //in = new BufferedReader(new FileReader("metro.txt"));
              out = System.out;
              
              long mod = (long)1e9 + 7;
              int n = nextInt();
              long[][] dp = new long[n+1][n+1];
              Character[] line = new Character[n+1];
              line[0] = 'a';
              for (int i = 1; i <= n; i++) {
                  line[i] = nextToken().charAt(0);
                  if(line[i-1] == 'f')//for
                  {
                      for (int j = 0; j < i; j++) {
                          dp[i][j+1] = dp[i-1][j];
                      }
                  }
                  else if(line[i-1] == 's')//simple
                  {
                      long temp = 0;
                      for(int j = i; j >=0; j--)
                      {
                          temp = (temp + dp[i-1][j]) % mod;
                          dp[i][j] = temp;
                      }
                  }
                  else dp[i][0] = 1;
              }
              long total = 0;
              for(int j = 0; j <= n; j++)
                  total = (total + dp[n][j]) % mod;
              out.println(total);
          }
          static String nextToken() throws IOException
          {
                  String line = "";
                  while(tok == null || !tok.hasMoreTokens()) {
                          if((line = in.readLine()) != null)
                                  tok = new StringTokenizer(line);
                          else 
                                  return null;
                  }
                  return tok.nextToken();
          }
          static int nextInt() throws NumberFormatException, IOException
          {
                  return Integer.parseInt(nextToken());
          }
          static long nextLong() throws NumberFormatException, IOException
          {
                  return Long.parseLong(nextToken());
          }
  
  }