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
/*
Things to notice:
1. do not calculate useless values
2. do not use similar names
 
Things to check:
1. submit the correct file
2. time (it is log^2 or log)
3. memory
4. prove your naive thoughts 
5. long long
6. corner case like n=0,1,inf or n=m
7. check if there is a mistake in the ds or other tools you use
8. fileio in some oi-contest

9. module on time 
10. the number of a same divisor in a math problem
11. multi-information and queries for dp and ds problems
*/
#include<bits/stdc++.h>
using namespace std;
#define int long long
#define fi first
#define se second
#define pii pair<long long,long long>
#define mp make_pair
#define pb push_back
const int mod=998244353;
const int inf=0x3f3f3f3f;
const int INF=1e18;
int n;
int a[20005],s[20005];
int cnt[50000005];
const int D=25000000; 
void solve()
{
	cin>>n;
	for(int i=1;i<=n;i++) cin>>a[i],s[i]=s[i-1]+a[i];
	int ans=0;
	for(int r2=1;r2<=n;r2++)
	{
		for(int l3=1;l3<=n;l3++) for(int r3=l3;r3<=n;r3++) cnt[-s[r3]+s[l3-1]+s[r2-1]+D]++;
		for(int l1=1;l1<=n;l1++) for(int r1=l1;r1<=n;r1++) ans+=cnt[s[r1]-s[l1-1]+s[r2]+D];
	}
	memset(cnt,0,sizeof(cnt));
	for(int l1=1;l1<=n;l1++) for(int r1=l1;r1<=n;r1++) cnt[s[r1]-s[l1-1]+D]++;
	int cnt0=0;
	for(int l1=1;l1<=n;l1++) for(int r1=l1;r1<=n;r1++)
	{
		int x=s[r1]-s[l1-1];
		if(!x) cnt0++,ans--;
		else ans-=3LL*cnt[-2LL*x+D];
	}
	ans-=3LL*cnt0*(cnt0-1);
	cout<<ans/6<<"\n";
}
signed main()
{
	ios::sync_with_stdio(0);
	cin.tie(0);
	int _=1;
//	cin>>_;
	while(_--) solve();
	return 0;
}