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
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
// {{{ file: buc.cc | time: 07:34 16.03.2024
#define _USE_MATH_DEFINES
#include <bits/stdc++.h>

#define each(...)    for (auto& __VA_ARGS__)
#define rep(i, b, e) for (int i = (b); i <= (e); i++)
#define rev(i, b, e) for (int i = (e); i >= (b); i--)
#define mp make_pair
#define mt make_tuple
#define x first
#define y second
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define endl '\n'
#define tC template<class

using namespace std;

tC T> using V = vector<T>;
tC T1, class T2> using P = pair<T1,T2>;
tC T, class C=greater<T>> using PQ = priority_queue<T,V<T>,C>;
tC T> int sz(const T& a) { return (int)a.size(); }
tC T> bool amin(T& a, T b) { return b < a ? a = b, 1 : 0; }
tC T> bool amax(T& a, T b) { return b > a ? a = b, 1 : 0; }

using ll = long long;
using pii = P<int,int>;
using pll = P<ll,ll>;
using vi = V<int>;
using vl = V<ll>;
using vs = V<string>;
using vpi = V<pii>;
using vpl = V<pll>;

const int oo = 1e9 + 1;
const ll OO = ll(1e18) + 1;

auto now() { return chrono::high_resolution_clock::now().time_since_epoch().count(); }
mt19937 rnd(4488);
tC T> T rand(T lo, T hi) { return uniform_int_distribution<T>{lo,hi}(rnd); }

struct Debug {
#ifdef SPONGE
  tC T>Debug operator<<(const T& x) {
    cerr<<"\033[1;33m"<<x<<"\033[0m";
#else
  tC T>Debug operator<<(const T&) {
#endif
    return *this;
  }
} dbg;
#define $(x) #x<<'='<<(x)<<' '

void boost()
{
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.precision(15);
  cout.setf(ios::fixed,ios::floatfield);
  cerr.precision(15);
  cerr.setf(ios::fixed,ios::floatfield);
}

namespace { void solve(); }
// }}}

int main()
{
  boost();
  //rnd.seed(now());
  int t=1;
  //cin>>t;
  rep(i,1,t){
    //cout<<"Case #"<<i<<": ";
    solve();
  }
}

namespace {

const int N=505;
const int O=5*500*20000;

int n,a[N],ile[2*O+1];
ll odp=0;

void solve()
{
  cin>>n;
  rep(i,1,n) cin>>a[i];
  rep(i,1,n) a[i]+=a[i-1];

  rep(i,0,n){
    rep(k0,0,n) rep(k1,k0+1,n){
      odp+=ile[O+a[i]+a[k1]-a[k0]];
    }
    rep(j0,0,n) rep(j1,j0+1,n){
      ile[O+a[i]+a[j0]-a[j1]]++;
    }
  }

  rep(i,0,2*O) ile[i]=0;

  rep(i,0,n){
    rep(j0,0,n) rep(j1,j0+1,n){
      odp-=3*ile[O+a[i]+2*(a[j1]-a[j0])];
    }
    ile[O+a[i]]++;
  }

  rep(i0,0,n) rep(i1,i0+1,n){
    if(a[i1]==a[i0]) odp+=2;
  }

  cout<<odp/6<<endl;
}

}