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

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

const int NMAX  = 212345;

int n;
char in[1123456];
ll pa[NMAX];
ll pb[NMAX];

int main()
{
	ll out = 0;
	scanf("%d %s", &n, in);
	fo(i,n)
	{
		pa[i+1]=pa[i];
		pb[i+1]=pb[i];
		if(in[i]=='X') pa[i+1]++;
		else pb[i+1]++;
	}
	for(ll e=1;e*e <= n;e++)
	{
		ll a = 4*e+4;
		ll b = e*e;
		ll s = a+b;
		for(int i=0;i+s<=n;i++)
		{
			int j=i+s;
			if(pa[j]-a == pa[i] && pb[j]-b == pb[i])
				out++;
			else
			if(pa[j]-b == pa[i] && pb[j]-a == pb[i])
				out++;
		}

	}
	printf("%lld\n", out);
	return 0;
}