#include<bits/stdc++.h>
using namespace std;
#define int long long
int a[61], n, dp[61][3];
signed main() {
	int n;
	string s;

	cin >> n;
	for (int i = 1; i <= n; i++) {
		cin >> s;
		if (s == "AND")a[i] = 0;
		else a[i] = 1;
	}
	dp[0][0] = dp[0][1] = 1;


	for (int i = 1; i <= n; i++) {
		if (a[i] == 0) {
			dp[i][0] += dp[i - 1][0];
			dp[i][0] += dp[i - 1][1];
			dp[i][0] += dp[i - 1][0];
			dp[i][1] += dp[i - 1][1];
		} else {
			dp[i][0] += dp[i - 1][0];
			dp[i][1] += dp[i - 1][1];
			dp[i][1] += dp[i - 1][0];
			dp[i][1] += dp[i - 1][1];
		}




	}

	cout << dp[n][1];
}