#include<bits/stdc++.h>
#define N 2000005
#define k (str[i]-'a'+1)
#define int long long
using namespace std;
const int modd=1e13+51;
int n,ans,num,h[N]; string str;
map<int,int>mp;
signed main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr); cout.tie(nullptr);
    cin>>n>>str; str=" "+str; mp[0]=1;
    list<int>stk; for(int i=1;i<=n;++i){
        if(stk.size() && stk.back()==str[i])stk.pop_back();
        else{
            stk.push_back(str[i]);
            h[stk.size()]=(h[stk.size()-1]*131+str[i])%modd;
        } ans+=mp[h[stk.size()]]; ++mp[h[stk.size()]];
    } cout<<ans; return 0;
}