//#pragma GCC optimize("Ofast")
//#pragma GCC optimize("unroll-loops")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ull = unsigned long long;
using db = double;
using ld = long double;
template<typename T> using V = vector<T>;
template<typename T> using VV = vector<vector<T>>;
#define fs first
#define sc second
#define pb push_back
#define mp make_pair
#define mt make_tuple
#define eb emplace_back
#define lb lower_bound
#define ub upper_bound
#define all(v) (v).begin(),(v).end()
#define siz(v) (ll)(v).size()
#define rep(i,a,n) for(ll i=a;i<(ll)(n);++i)
#define repr(i,a,n) for(ll i=n-1;(ll)a<=i;--i)
#define ENDL '\n'
typedef pair<int,int> Pi;
typedef pair<ll,ll> PL;
constexpr ll mod = 1000000007; // 998244353;
constexpr ll INF = 1000000099;
constexpr ll LINF = (ll)(1e18 +99);
const ld PI = acos((ld)-1);
const vector<ll> dx={-1,1,0,0},dy={0,0,-1,1};
template<typename T,typename U> inline bool chmin(T& t, const U& u){if(t>u){t=u;return 1;}return 0;}
template<typename T,typename U> inline bool chmax(T& t, const U& u){if(t<u){t=u;return 1;}return 0;}
template<typename T> inline T gcd(T a,T b){return b?gcd(b,a%b):a;}

template<typename T,typename Y> inline T mpow(T a, Y n) {
  T res = 1;
  for(;n;n>>=1) {
    if (n & 1) res = res * a;
    a = a * a;
  }
  return res;
}

template <typename T> V<T> prefix_sum(const V<T>& v) {
  int n = v.size();
  V<T> ret(n + 1);
  rep(i, 0, n) ret[i + 1] = ret[i] + v[i];
  return ret;
}

template<typename T>
istream& operator >> (istream& is, vector<T>& vec){
  for(auto&& x: vec) is >> x;
  return is;
}

template<typename T,typename Y>
ostream& operator<<(ostream& os,const pair<T,Y>& p){
  return os<<"{"<<p.fs<<","<<p.sc<<"}";
}

template<typename T> ostream& operator<<(ostream& os,const V<T>& v){
  os<<"{";
  for(auto e:v)os<<e<<",";
  return os<<"}";
}

template<typename ...Args>
void debug(Args&... args){
  for(auto const& x:{args...}){
    cerr<<x<<' ';
  }
  cerr<<ENDL;
}



signed main(){
  cin.tie(0);cerr.tie(0);ios::sync_with_stdio(false);
  cout<<fixed<<setprecision(20);
  ll n;cin>>n;
  string s;cin>>s;

  V<ll> asum(n+1,0),tsum=asum,csum=asum,gsum=asum;

  rep(i,0,n){
    asum[i+1]=asum[i]+int(s[i]=='A');
    tsum[i+1]=tsum[i]+int(s[i]=='T');
    csum[i+1]=csum[i]+int(s[i]=='C');
    gsum[i+1]=gsum[i]+int(s[i]=='G');
  }

  ll ans=0;
  rep(i,0,n){
    rep(j,i+2,n+1){
      if(asum[j]-asum[i]==tsum[j]-tsum[i] && csum[j]-csum[i]==gsum[j]-gsum[i])++ans;
    }
  }

  cout<<ans<<ENDL;
}
//! ( . _ . ) ! 
//CHECK overflow,vector_size,what to output?
#include <bits/stdc++.h>

using namespace std;
#define inf 1000000000
#define unvisited -1
#define visited 1
#define eps 1e-9
#define mp make_pair
#define pb push_back
#define pi acos(-1.0)
#define uint64 unsigned long long
#define FastSlowInput ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
#define debug if(true)
typedef long long ll;
typedef vector<int> vi;
typedef pair<int,int> ii;
typedef vector<ii> vii;

int main(){
	int n,i,j;
	string s;
	
	map<char, int> mapper;
	mapper['A'] = 0;
	mapper['T'] = 1;
	mapper['C'] = 2;
	mapper['G'] = 3;
	while(scanf("%d",&n) !=EOF){
		cin>>s;
		int ans = 0;
		for(i=0;i<n;i++){
			int cnt[4];
			memset(cnt, 0, sizeof cnt);
			for(j=i;j<n;j++){
				char c = s[j];
				cnt[mapper[c]]++;
				if(cnt[0] == cnt[1] && cnt[2] == cnt[3]){
					ans++;
				}
			}
		}
		printf("%d\n",ans);	
	}
	
	
	return 0;
};