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

typedef long long ll;
const int maxn=2e6+10;
const int base=13331;
const int mod1=1e9+3579;
const int mod2=998244353;
const int inv1=804968750;
const int inv2=814485322;

inline int read(){
    int x=0,w=1;char c=getchar();
    while(c<'0'||c>'9'){if(c=='-')w=-1;c=getchar();}
    while(c<='9'&&c>='0'){x=(x<<3)+(x<<1)+c-'0';c=getchar();}
    return x*w;
}

int n;
char s[maxn];
ll ans;
struct HashTable{
    const static int MOD=5000011;
    int head[MOD],tot;
    int nxt[maxn],siz[maxn];
    ll val[maxn];
    inline void insert(ll k){
        int p=k%MOD;
        for(int i=head[p];i;i=nxt[i]){
            if(val[i]==k) return ++siz[i],void();
        }
        ++tot;
        nxt[tot]=head[p],val[tot]=k,siz[tot]=1;
        head[p]=tot;
    }
    inline void calc(){
        for(int i=1;i<=tot;++i){
            ans+=1ll*siz[i]*(siz[i]-1)/2;
        }
    }
}mp;

int st[maxn],top;
int h1,h2;

int main(){
    n=read();
    scanf("%s",s+1);
    mp.insert(0);
    for(int i=1;i<=n;++i){
        if(top&&s[st[top]]==s[i]){
            h1=1ll*(h1-s[st[top]]+mod1)*inv1%mod1;
            h2=1ll*(h2-s[st[top]]+mod2)*inv2%mod2;
            --top;
        }
        else{
            st[++top]=i;
            h1=(1ll*h1*base+s[i])%mod1;
            h2=(1ll*h2*base+s[i])%mod2;
        }
        mp.insert(1ll*h1*mod2+h2);
    }
    mp.calc();
    printf("%lld\n",ans);
    return 0;
}