#include <bits/stdc++.h>
using namespace std;

typedef long long ll;

const ll mod = ll(1e9) + 7;

int n;
vector<vector<ll> > dp;
vector<char> arr;

int main (int argc, char *argv[])
{
    scanf("%d", &n);
    dp.resize(n);
    for(int i = 0; i < n; ++i)
    {
        dp[i].resize(n, 0);
    }
    arr.resize(n);
    scanf(" %c", &arr[0]);
    dp[0][0] = 1;
    for(int i = 1; i < n; ++i)
    {
        scanf(" %c", &arr[i]);
        if(arr[i - 1] == 'f')
        {
            for(int j = 0; j < n - 1; ++j)
            {
                dp[i][j + 1] = dp[i - 1][j];
                dp[i][j + 1] %= mod;
            }
        } else
        {
            ll sum = 0;
            for(int j = n - 1; j >= 0; --j)
            {
                sum += dp[i - 1][j];
                sum %= mod;
                dp[i][j] = sum;
            }
        }
    }
    ll sum = 0;
    for(int i = 0; i < n; ++i)
    {
        sum += dp[n - 1][i];
    }
    printf("%lld", sum % mod);

    return 0;
}