#include <bits/stdc++.h>
using namespace std;
#define int long long
const int N=1e6+10;
const int INF=0x3f3f3f3f;
int n,ans;
string s;
signed main(){
	cin>>n>>s;
	for(int i=0;i<n;i++){
		int s1=0,s2=0,x;
		x=i;
		while(x+1<n&&s[x+1]!=s[i]){
			x++;
			s1++;
		}
		x=i;
		while(x-1>=0&&s[x-1]!=s[i]){
			x--;
			s2++;
		}
		if(s1>1){
			ans+=(s1-1);
		}
		if(s2>1){
			ans+=(s2-1);
		}
		if(s1>0&&s2>0){
			ans+=s1*s2;
		}
	}
	cout<<ans<<endl;
	return 0;
}