#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];
map<int, map<int, int>> counts;

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