#include<bits/stdc++.h>
#define all(x) (x).begin(),(x).end()
typedef long long ll;
#define rep(i,n) for(ll i=0, i##_len=(n); i<i##_len; ++i)
#define REP(i,num,n) for(ll i=num, i##_len=(n); i<i##_len; ++i)
#define reprrev(i,a,b) for(int i=b-1;i>=a;i--)
#define reprev(i,n) reprrev(i,0,n)
using namespace std;
#define sz(x) ((int)(x).size())
#define ZERO(a) memset(a,0,sizeof(a))
#define MINUS(a) memset(a,0xff,sizeof(a))
#define MEMSET(v, h) memset((v), h, sizeof(v))
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
#define pb push_back
#define mp make_pair
#define y0 y3487465
#define y1 y8687969
#define j0 j1347829
#define j1 j234892
ll gcd(ll a,ll b){return b?gcd(b,a%b):a;}
const ll INF = 1LL<<60;
 
const int MAX = 510000;
const int MOD = 1000000007;
 
long long fac[MAX], finv[MAX], inv[MAX];
 
// テーブルを作る前処理
void COMinit() {
	fac[0] = fac[1] = 1;
	finv[0] = finv[1] = 1;
	inv[1] = 1;
	for (int i = 2; i < MAX; i++) {
		fac[i] = fac[i - 1] * i % MOD;
		inv[i] = MOD - inv[MOD%i] * (MOD / i) % MOD;
		finv[i] = finv[i - 1] * inv[i] % MOD;
	}
}
 
// 二項係数計算
long long COM(int n, int k) {
	if (n < k) return 0;
	if (n < 0 || k < 0) return 0;
	return fac[n] * (finv[k] * finv[n - k] % MOD) % MOD;
}
 
struct UnionFind {
	vector<int> par, rank;
 
	UnionFind(int n) : par(n, -1), rank(n, 0) { }
	void init(int n) { par.assign(n, -1), rank.assign(n, 0); }
 
	int root(int x) {
		if (par[x] == -1) return x;
		else return par[x] = root(par[x]);
	}
 
	bool issame(int x, int y) {
		return root(x) == root(y);
	}
 
	bool merge(int x, int y) {
		x = root(x); y = root(y);
		if (x == y) return false;
		if (rank[x] < rank[y]) swap(x, y);
		if (rank[x] == rank[y]) ++rank[x];
		par[y] = x;
		return true;
	}
};
 
int main() {
	ll N;
	cin >> N;
	string s;
	cin >> s;
	ll ans = 0;
	vector<ll> u(N);
	vector<ll> m(N);
	vector<ll> g(N);
	ll ui = 0;
	ll mi = 0;
	ll gi = 0;
	rep(i, N) {
		if (s[i] == 'U') {
			u[ui] = i;
			++ui;
		}
		if (s[i] == 'M') {
			m[mi] = i;
			++mi;
		}
		if (s[i] == 'G') {
			g[gi] = i;
			++gi;
		}
	}
	u.resize(ui);
	m.resize(mi);
	g.resize(gi);
	rep(i, u.size()) {
		rep(j, m.size()) {
			auto it = find(g.begin(), g.end(), u[i] + 2 * (m[j] - u[i]));
			if (it != g.end()) {
				++ans;
			}
			else {
				continue;
			}
		}
	}
	cout << ans << endl;
}