#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define fore(i, a, b) for (int i = (a), _b = (b); i < _b; ++i)
#define fort(i, a, b) for (int i = (a), _b = (b); i <= _b; ++i)
#define fordt(i, a, b) for (int i = (a), _b = (b); i >= _b; --i)
#define forde(i, a, b) for (int i = (a), _b = (b); i > _b; --i)
#define trav(a, x) for (auto& a : x)
#define sz(x) ((int)(x).size())
#define all(x) (x).begin(), (x).end()
using namespace std;
using namespace __gnu_pbds;
template<class A, class B> bool maxi(A &a, const B &b) {return (a < b) ? (a = b, true):false;};
template<class A, class B> bool mini(A &a, const B &b) {return (a > b) ? (a = b, true):false;};
typedef int64_t i64;
typedef pair<int,int> _ii;
typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;
constexpr int maxn=2e5+7;
constexpr i64 oo=1e9+7;
int n, a[5007], dp[5007][5007];
void solve() {
cin >> n;
fort(i, 1, n) cin >> a[i];
fort(mid, 1, n) {
fore(i, 1, mid)
maxi(dp[i][mid - 1], dp[i - 1][mid - 1]);
int r = mid, l = mid - 1, sum_up = a[r], sum_down = a[l], cnt = 0;
while(r < n || l > 1) {
if(r >= n) {
sum_down += a[--l];
maxi(dp[mid][r], dp[l][mid - 1] + cnt);
}
else if(l <= 1) {
sum_up += a[++r];
// maxi(dp[mid][r], dp[l][mid - 1] + cnt);
maxi(dp[mid][r], dp[mid][r - 1]);
}
else {
if(sum_up >= sum_down) {
sum_down += a[--l];
}
else {
sum_up += a[++r];
maxi(dp[mid][r], dp[mid][r - 1]);
}
// else {
// maxi(dp[mid][r], dp[l][mid - 1] + cnt);
// maxi(dp[mid][r + 1], dp[mid][r]);
// sum_up += a[++r];
// sum_down += a[--l];
// ++cnt;
// maxi(dp[mid][r], dp[l][mid - 1] + cnt);
// }
}
if(r - mid >= 1 && mid - l >= 2 && sum_down - a[l] == sum_up - a[r]) ++cnt;
maxi(dp[mid][r], dp[l][mid - 1] + cnt);
}
if(l > 1) maxi(dp[mid][r], dp[l - 1][mid - 1] + cnt);
}
int ans = 0;
fort(i, 1, n) maxi(ans, dp[i][n]);
cout << ans << '\n';
}
#define NAME "test."
int main() {
ios_base::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
if(fopen(NAME"inp", "r")) {
freopen(NAME"inp", "r", stdin);
freopen(NAME"out", "w", stdout);
}
int t=1;
while(t--) solve();
}
