#include <iostream>
#include <iomanip>
#include <vector>
#include <set>
#include <unordered_set>
#include <map>
#include <unordered_map>
#include <queue>
#include <deque>
#include <stack>
#include <algorithm>
#include <numeric>
#include <string>
#include <sstream>
#include <cmath>
#include <cstring>
#include <assert.h>
#include <utility>
#include <tuple>
#include <array>
#include <bitset>
#include <cstdlib>

using int64 = long long;

template <typename T = int>
struct Range {
    struct RangeIterator {
        T i, step;

        RangeIterator(T i, T step): i{i}, step{step} {}

        T& operator*() { return i; }
        RangeIterator& operator++() {
            i += step;
            return *this;
        }
        bool operator!=(const RangeIterator& rhs) const {
            return (step > 0 && i < rhs.i) || (step < 0 && i > rhs.i);
        }
    };

    T start, stop, step;

    Range(T start, T stop, T step): start{start}, stop{stop}, step{step} {}
    Range(T start, T stop): Range(start, stop, 1) {}
    Range(T stop): Range(0, stop, 1) {}
    
    RangeIterator begin() const { return RangeIterator(start, step); }
    RangeIterator end() const { return RangeIterator(stop, step); }
};

int main() {
    std::cin.tie(nullptr);
    std::ios::sync_with_stdio(false);

    int n;
    std::cin >> n;

    std::string s;
    std::cin >> s;

    int ans = 0;
    for (const int j : Range<>(1, n - 1)) {
        for (const int d : Range<>(1, n)) {
            int i = j - d,
                k = j + d;
            if (0 <= i && k < n && s[i] == 'U' && s[j] == 'M' && s[k] == 'G') {
                ans++;
            }
        }
    }
    std::cout << ans << std::endl;

    return 0;
}