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

int main(){
    int n; cin >> n;
    string s; cin >> s;

    vector<vector<vector<bool>>> dp(n, vector<vector<bool>>(n, vector<bool>(n, false)));
    // dp[i][j][k] = can k win in range [i, j]

    for (int i = 0; i < n; i++){
        dp[i][i][i] = true; // base cases
    }

    for (int sz = 1; sz < n; sz++) for (int l = 0; l < n - sz; l++){
        int r = l + sz;

        for (int m = l; m < r; m++){
            vector <int> wy(3, 0), wx(3, 0);

            // 0 -> fire, 1 -> water, 2 -> grass

            for (int x = l; x <= m; x++){
                if (dp[l][m][x]){
                    if (s[x] == 'F') wx[0]++;
                    else if (s[x] == 'W') wx[1]++;
                    else wx[2]++;
                }
            }

            for (int y = m + 1; y <= r; y++){
                if (dp[m + 1][r][y]){
                    if (s[y] == 'F') wy[0]++;
                    else if (s[y] == 'W') wy[1]++;
                    else wy[2]++;
                }
            }

            for (int x = l; x <= m; x++){
                if (dp[l][m][x]){
                    if (s[x] == 'F' && (wy[0] > 0 || wy[2] > 0)) dp[l][r][x] = true; // check if there are any y's that you can beat, fire can beat fire and grass types
                    if (s[x] == 'W' && (wy[1] > 0 || wy[0] > 0)) dp[l][r][x] = true;
                    if (s[x] == 'G' && (wy[2] > 0 || wy[1] > 0)) dp[l][r][x] = true;
                }
            }

            for (int y = m + 1; y <= r; y++){
                if (dp[m + 1][r][y]){
                    if (s[y] == 'F' && (wx[0] > 0 || wx[2] > 0)) dp[l][r][y] = true;
                    if (s[y] == 'W' && (wx[1] > 0 || wx[0] > 0)) dp[l][r][y] = true;
                    if (s[y] == 'G' && (wx[2] > 0 || wx[1] > 0)) dp[l][r][y] = true;
                }
            }
        }
    }

    int ans = 0;
    for (int i = 0; i < n; i++) ans += dp[0][n - 1][i]; // add 1 if i is possible winner in whole array

    cout << ans << "\n";
    return 0;
}