#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
#define fi first
#define se second
#define vi vector<int>
#define vll vector<long long>
#define pii pair<int, int>
#define pll pair<long long, long long>
#define pb push_back
#define mp make_pair
#define eb emplace_back
#define all(x) (x).begin(), (x).end()
#define sz(x) (int)(x).size()
mt19937 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
mt19937_64 rng64(chrono::high_resolution_clock::now().time_since_epoch().count());
inline int rand(int l,int r){return uniform_int_distribution<int>(l, r)(rng);}
inline ll rand(ll l,ll r){return uniform_int_distribution<ll>(l, r)(rng64);}
#ifdef DEBUG
auto&operator<<(auto&o,pair<auto,auto>p){return o<<"("<<p.first<<", "<<p.second<<")";}
auto operator<<(auto&o,auto x)->decltype(x.end(),o){o<<"{";int i=0;for(auto e:x)o<<","+!i++<<e;return o<<"}";}
#define debug(X...)cerr<<"["#X"]: ",[](auto...$){((cerr<<$<<"; "),...)<<endl;}(X)
#else
#define debug(...){}
#endif
struct custom_hash {
static uint64_t splitmix64(uint64_t x) {
x += 0x9e3779b97f4a7c15;
x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
return x ^ (x >> 31);
}
size_t operator()(uint64_t x) const {
static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
return splitmix64(x + FIXED_RANDOM);
}
};
struct pair_hash{
size_t operator()(const pair<int,int>&x)const{
return hash<long long>()(((long long)x.first)^(((long long)x.second)<<32));
}
};
const int MAXN = 5e3 + 7;
int dp[MAXN][MAXN];
int dp2[MAXN][MAXN];
vector<pii> add[MAXN];
int ptr[MAXN];
int A[MAXN];
int pref[MAXN];
int n;
void preprocessing(){
for(int i = 1; i <= n; i++){
pref[i] = pref[i - 1] + A[i];
}
for(int i = 1; i <= n; i++){
int wsk = i - 1;
int sum = A[i];
int wskR = i + 1;
int sumR = A[i + 1];
while(wskR < n && wsk > 0){
if(sum == sumR){
add[i].pb(mp(wsk, wskR));
// cerr << i << ' ' << wsk << ' ' << wskR << '\n';
sum += A[wsk];
wsk--;
wskR++;
sumR += A[wskR];
continue;
}
if(sumR < sum){
wskR++;
sumR += A[wskR];
}else{
sum += A[wsk];
wsk--;
}
}
}
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(NULL);
cout.tie(NULL);
cin >> n;
for(int i = 1; i <= n; i++){
cin >> A[i];
}
preprocessing();
for(int i = 1; i <= n; i++){
for(int j = 0; j <= i - 1; j++){
if(ptr[j]){
dp[i][j] = dp[add[j][ptr[j] - 1].se][j];
}
while(ptr[j] < sz(add[j]) && add[j][ptr[j]].se < i){
dp[i][j] = max(dp[i][j], ptr[j] + 1 + dp2[j][add[j][ptr[j]].fi]);
ptr[j]++;
}
//cerr << i << ' ' << j << ' ' << dp[i][j] << '\n';
dp2[i][j] = dp[i][j];
if(j){
dp2[i][j] = max(dp2[i][j], dp2[i][j - 1]);
}
}
}
cout << dp2[n][n - 1] << '\n';
return 0;
}
