#include <bits/extc++.h>
using namespace std;
#include <atcoder/all>
using namespace atcoder;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
#define repp(i, m, n) for(int i = (int)(m); i < (int)n; i++)
#define rep(i, n) for(int i = 0; i < (int)(n); i++)
#define fore(x, a) for (auto &x : a)
#define rall(x) (x).rbegin(),(x).rend()
#define all(x) (x).begin(),(x).end()
#define co(a, x, b) (a <= x && x < b)
#define INF ((1LL<<62)-(1LL<<31))
typedef pair<int, int> pii;
typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vl;
int main() {
int n;
string s;
cin >> n >> s;
int ans = 0;
rep(i, n) {
repp(j, i, n) {
repp(k, j, n) {
if (s[i] == 'E' && s[j] == 'G' && s[k] == 'F') ans++;
}
}
}
cout << ans << endl;
}