n = int(input())
s = input()
ret = 0
for i in range(n):
    for j in range(i+1, n):
        for k in range(j+1, n):
            if j-i!=k-j:
                continue
            if s[i]=='U' and s[j]=='M' and s[k]=='G':
                ret += 1
print(ret)