1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
// Arti1990, II UWr

#include <bits/stdc++.h>

#define forr(i, n)                  for(int i=0; i<n; i++)
#define FOREACH(iter, coll)         for(auto iter = coll.begin(); iter != coll.end(); ++iter)
#define FOREACHR(iter, coll)        for(auto iter = coll.rbegin(); iter != coll.rend(); ++iter)
#define lbound(P,K,FUN)             ({auto SSS=P, PPP = P-1, KKK=(K)+1; while(PPP+1!=KKK) {SSS = (PPP+(KKK-PPP)/2); if(FUN(SSS)) KKK = SSS; else PPP = SSS;} PPP;})
#define testy()                     int _tests; cin>>_tests; FOR(_test, 1, _tests)
#define CLEAR(tab)                  memset(tab, 0, sizeof(tab))
#define CONTAIN(el, coll)           (coll.find(el) != coll.end())
#define FOR(i, a, b)                for(int i=a; i<=b; i++)
#define FORD(i, a, b)               for(int i=a; i>=b; i--)
#define MP                          make_pair
#define PB                          push_back
#define ff                          first
#define ss                          second
#define deb(X)                      X;
#define SIZE(coll) 					((int)coll.size())

#define M 1000000007
#define INF 1000000007LL

using namespace std;

int n, m, a;
int tab[1000007], pref[1000007];
long long ile_[40'000'017];
long long *ile = ile_ + 20'000'007;
vector <int> vals;
set <int> valss;

int solve()
{
    cin >> n;
    FOR(i, 1, n)
    {
        cin >> tab[i];
        pref[i] = pref[i-1] + tab[i];
    }

    FOR(i, 1, n)
    {
        int suma = 0;
        FOR(j, i, n)
        {
            suma += tab[j];
            vals.PB(suma);
            valss.insert(suma);
            ile[suma]++;
        }
    }

    long long res = 0, rm = 0;
    /*
    for(auto el : vals)
        for(auto el2 : vals)
        {
            res += ile[-el-el2];
            //if(ile[-el-el2] > 0)
            //    cout << el << " i " << el2 << " daja " << ile[-el-el2] << '\n';
        }
    */
    for(auto el : valss)
    {
        if(el != 0)
            rm -= 3*ile[el] * ile[-2*el];
    }
    rm -= ile[0]*ile[0]*ile[0];
    rm /= 6;
    rm += ile[0]*(ile[0]-1)*(ile[0]-2) / 6;

    FOR(i, 1, n)
    {
        for(auto el : vals)
        {
            res += ile[-(el+pref[i])];
        }
        for(auto el : vals)
        {
            ile[el-pref[i]]++;   
        }
    }
    //cout << res << '\n';

    cout << res/6 + rm << '\n';

    return 0;
}

int main()
{
    std::ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    solve();

    return 0;
}