N = int(input())
S = input()
#print(N, S)

ans = 0
for i in range(N):
    for j in range(N):
        for k in range(N):
            if S[i] == 'U' and S[j] == 'M' and S[k] == 'G' and j - i == k -j:
                    ans += 1
        
print(ans)