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

int main()
{
    vector<int>v={1,-1,1,-1,1,1,1,-1,-1};
    int n=v.size();
    unordered_map<int,int>mp;
    mp[0]=1;
    int sum=0;
    int count=0;
    for(int i=0;i<n;i++){
        sum=sum+v[i];
        if(mp.find(sum)!=mp.end()){
            count+=mp[sum];
        }
        mp[sum]++;
    }
    
    cout<<count<<endl;

    return 0;
}