source_code: 
  
  import java.util.Arrays;
  
  public class Main {
  
  	private static void solve() {
  		int n = ni();
  		String[] lines = new String[n];
  		for(int i = 0; i < n; i ++) {
  			lines[i] = next();
  		}
  		int mod = 1000000000 + 7;
  		
  		long[][] dp = new long[2][n + 1];
  		dp[0][0] = 1;
  		for (int i = 0; i < n; i ++) {
  			int from = i % 2;
  			int to = (i + 1) % 2;
  			boolean flg = i == 0 || lines[i - 1].equals("s");
  			if (flg) {
  				long v = Arrays.stream(dp[from]).sum();
  				for (int j = 0; j <= n; j ++) {
  					dp[to][j] += v;
  					dp[to][j] %= mod;
  					v -= dp[from][j];
  				}
  			} else {
  				for (int j = 0; j < n; j ++) {
  					dp[to][j + 1] += dp[from][j];
  					dp[to][j + 1] %= mod;
  				}
  			}
  			Arrays.fill(dp[from], 0);
  		}
  		long ret = Arrays.stream(dp[n % 2]).sum() % mod;
  		System.out.println(ret);
  	}
  	
  
  	public static void main(String[] args) {
  		new Thread(null, new Runnable() {
  			@Override
  			public void run() {
  				long start = System.currentTimeMillis();
  				String debug = args.length > 0 ? args[0] : null;
  				if (debug != null) {
  					try {
  						is = java.nio.file.Files.newInputStream(java.nio.file.Paths.get(debug));
  					} catch (Exception e) {
  						throw new RuntimeException(e);
  					}
  				}
  				reader = new java.io.BufferedReader(new java.io.InputStreamReader(is), 32768);
  				solve();
  				out.flush();
  				tr((System.currentTimeMillis() - start) + "ms");
  			}
  		}, "", 64000000).start();
  	}
  
  	private static java.io.InputStream is = System.in;
  	private static java.io.PrintWriter out = new java.io.PrintWriter(System.out);
  	private static java.util.StringTokenizer tokenizer = null;
  	private static java.io.BufferedReader reader;
  
  	public static String next() {
  		while (tokenizer == null || !tokenizer.hasMoreTokens()) {
  			try {
  				tokenizer = new java.util.StringTokenizer(reader.readLine());
  			} catch (Exception e) {
  				throw new RuntimeException(e);
  			}
  		}
  		return tokenizer.nextToken();
  	}
  
  	private static double nd() {
  		return Double.parseDouble(next());
  	}
  
  	private static long nl() {
  		return Long.parseLong(next());
  	}
  
  	private static int[] na(int n) {
  		int[] a = new int[n];
  		for (int i = 0; i < n; i++)
  			a[i] = ni();
  		return a;
  	}
  
  	private static char[] ns() {
  		return next().toCharArray();
  	}
  
  	private static long[] nal(int n) {
  		long[] a = new long[n];
  		for (int i = 0; i < n; i++)
  			a[i] = nl();
  		return a;
  	}
  
  	private static int[][] ntable(int n, int m) {
  		int[][] table = new int[n][m];
  		for (int i = 0; i < n; i++) {
  			for (int j = 0; j < m; j++) {
  				table[i][j] = ni();
  			}
  		}
  		return table;
  	}
  
  	private static int[][] nlist(int n, int m) {
  		int[][] table = new int[m][n];
  		for (int i = 0; i < n; i++) {
  			for (int j = 0; j < m; j++) {
  				table[j][i] = ni();
  			}
  		}
  		return table;
  	}
  
  	private static int ni() {
  		return Integer.parseInt(next());
  	}
  
  	private static void tr(Object... o) {
  		if (is != System.in)
  			System.out.println(java.util.Arrays.deepToString(o));
  	}
  }
  