#include <bits/stdc++.h>
using namespace std;
#define pii pair<int,int>
#define fi first
#define se second
const int N = 5e3+5;
int n,a[N],dp[N][N],pre[N][N],check[N*N];
signed main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cin >> n;
for(int i = 1; i <= n; i++) cin >> a[i];
for(int i = 2; i <= n; i++){
int cur = 0;
for(int j = i-1; j >= 2; j--){
cur += a[j];
check[cur] = 1;
}
int l = i-1;
int cur1 = 0;
int cur2 = 0;
int cnt = 0;
bool ck = true;
for(int j = i; j <= n; j++){
while(cur2 <= cur1){
if(l == 0){
ck = false;
break;
}
cur2 += a[l];
l--;
}
if(ck == false) break;
dp[i][j] = pre[i-1][l+1]+cnt;
cur1 += a[j];
if(check[cur1]) cnt++;
}
cur = 0;
for(int j = i-1; j >= 2; j--){
cur += a[j];
check[cur] = 0;
}
for(int j = 1; j <= i; j++) pre[i][j] = max(pre[i][j-1],dp[j][i]);
}
int ans = 0;
for(int i = 1; i <= n; i++) ans = max(ans,dp[i][n]);
cout << ans;
}
