#include<bits/stdc++.h>
using namespace std;
using ll = long long;

#define fo(a,b) for(int a=0;a<(b);a++)

const int START = 123456;

int n;
char in[1123456];
unordered_map<ll, int> counts;

ll join(ll a, ll b)
{
	if(a<0 || b<0) return -1;
	return (a<<30) + b;
}

int main()
{
	ll out = 0;
	scanf("%d %s", &n, in);
	ll as=0;
	ll bs=0;
	fo(i,n)
	{
		counts[join(as, bs)]++;
		if(in[i]=='X') bs++;
		else as++;
		for(ll e=1;e*e <= as;e++)
			out += counts[join(as-e*e, bs-4*e-4)];
		for(ll e=1;e*e <= bs;e++)
			out += counts[join(as-4*e-4, bs-e*e)];
	}
	printf("%lld\n", out);
	return 0;
}