#include <bits/stdc++.h>
using namespace std;
template<class T, class U>
void ckmin(T &a, U b)
{
if (a > b) a = b;
}
template<class T, class U>
void ckmax(T &a, U b)
{
if (a < b) a = b;
}
#define MP make_pair
#define PB push_back
#define LB lower_bound
#define UB upper_bound
#define fi first
#define se second
#define FOR(i, a, b) for (auto i = (a); i < (b); i++)
#define FORD(i, a, b) for (auto i = (a) - 1; i >= (b); i--)
#define SZ(x) ((int) (x).size())
#define ALL(x) (x).begin(), (x).end()
const int MAXN = 5013;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<pii> vpi;
typedef vector<pll> vpl;
int N;
int arr[MAXN], pref[MAXN];
int dp[MAXN][MAXN];
int ans;
int seg[4 * MAXN], lazy[4 * MAXN];
void build(int w, int L, int R, int k)
{
lazy[w] = 0;
if (L == R)
{
seg[w] = dp[L][k];
return;
}
int mid = (L + R) >> 1;;
build(w << 1, L, mid, k);
build(w << 1 | 1, mid + 1, R, k);
seg[w] = max(seg[w << 1], seg[w << 1 | 1]);
}
void push(int w, int L, int R)
{
if (!lazy[w]) return;
seg[w] += lazy[w];
if (L != R)
{
lazy[w << 1] += lazy[w];
lazy[w << 1 | 1] += lazy[w];
}
lazy[w] = 0;
return;
}
void update(int w, int L, int R, int a, int b)
{
push(w, L, R);
if (b < L || R < a)
{
return;
}
if (a <= L && R <= b)
{
lazy[w]++;
push(w, L, R);
return;
}
int mid = (L + R) >> 1;
update(w << 1, L, mid, a, b);
update(w << 1 | 1, mid + 1, R, a, b);
seg[w] = max(seg[w << 1], seg[w << 1 | 1]);
}
int32_t main()
{
ios_base::sync_with_stdio(false); cin.tie(0);
cout << fixed << setprecision(12);
cerr << fixed << setprecision(4);
cin >> N;
FOR(i, 0, N)
{
cin >> arr[i];
pref[i + 1] = pref[i] + arr[i];
}
// dp[0][0] = 0;
FOR(i, 1, N + 1)
{
int iter = i - 1;
FOR(j, i, N + 1)
{
// dp[i][j] = 0;
// FOR(k, 1, i)
// {
// ckmax(dp[i][j], dp[k][i - 1]);
// }
dp[i][j] = seg[1];
int c = 2 * pref[i - 1] - pref[j];
while(iter != 0 && pref[iter] > c)
{
iter--;
}
// cerr << "dp " << i << ' ' << j << " = " << dp[i][j] << endl;
if (pref[iter] == c)
{
// FOR(k, 1, iter + 1)
// {
// // cerr << "ADD " << k << ' ' << i - 1 << endl;
// dp[k][i - 1]++;
// }
update(1, 1, i - 1, 1, iter);
}
//i...j. that means you use i-1....j-1.
//count how many s i-2...k = si-1...c
//pref[i-1] - pref[k] = pref[j] - pref[i - 1].
//pref[k] = 2 pref[i - 1] - pref[j]
//find dp[i][j].
//dp[i][j] = max(dp[i][j], dp[k][i - 1] + c(k, i, j))
//c(k, i, j) is # of positions l such that s[k] +
//there's always some poition
}
build(1, 1, i, i);
}
FOR(i, 1, N + 1)
{
ckmax(ans, dp[i][N]);
}
cout << ans << '\n';
return 0;
}
