#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
#ifdef _WIN32
#define getchar_unlocked _getchar_nolock
#endif
//~ #define int long long
#define mp make_pair
#define mt make_tuple
#define pb push_back
#define ppb pop_back
#define eb emplace_back
#define g0(a) get<0>(a)
#define g1(a) get<1>(a)
#define g2(a) get<2>(a)
#define g3(a) get<3>(a)
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
using db = double;
using ll = long long;
using ld = long double;
using ii = pair<int, int>;
using iii = tuple<int, int, int>;
using iiii = tuple<int, int, int, int>;
template<class key, class value = null_type, class cmp = less<key> >
using ordered_set = tree<key, value, cmp, rb_tree_tag, tree_order_statistics_node_update>;
int N, ans, t[10005], d[5005], p[5005], dp[5005][5005];
const int h = sizeof(int) * 8 - __builtin_clz(5000);
void apply(int p, int value) {
t[p] += value;
if (p < N) d[p] += value;
}
void build(int p) {
while (p > 1) p >>= 1, t[p] = max(t[p<<1], t[p<<1|1]) + d[p];
}
void push(int p) {
for (int s = h; s > 0; --s) {
int i = p >> s;
if (d[i] != 0) {
apply(i<<1, d[i]);
apply(i<<1|1, d[i]);
d[i] = 0;
}
}
}
void inc(int l, int r, int value) {
l += N, r += N;
int l0 = l, r0 = r;
for (; l < r; l >>= 1, r >>= 1) {
if (l&1) apply(l++, value);
if (r&1) apply(--r, value);
}
build(l0);
build(r0 - 1);
}
int query(int l, int r) {
l += N, r += N;
push(l);
push(r - 1);
int res = -2e9;
for (; l < r; l >>= 1, r >>= 1) {
if (l&1) res = max(res, t[l++]);
if (r&1) res = max(t[--r], res);
}
return res;
}
main() {
ios::sync_with_stdio(0);
cin.tie(0);
cin >> N;
for (int i = 1; i <= N; i++) {
cin >> p[i];
p[i] += p[i - 1];
}
for (int j = N; j >= 1; j--) {
memset(t, 0, sizeof t);
memset(d, 0, sizeof d);
for (int k = j + 1; k <= N; k++) {
inc(k - 1, k, dp[j + 1][k]);
}
int ptr = j + 1;
for (int i = j; i >= 1; i--) {
int ans = -1;
while (ptr <= N && p[ptr] - p[j] < p[j] - p[i - 1]) ptr++;
if (ptr <= N && p[ptr] - p[j] == p[j] - p[i - 1]) ans = ptr;
dp[i][j] = query(0, N);
//~ cout << "DP " << i << ' ' << j << ' ' << root->val << '\n';
if (ans != -1) {
inc(ans, N, 1);
//~ cout << " + " << i << ' ' << ans << '\n';
}
}
}
for (int i = 1; i <= N; i++) {
ans = max(ans, dp[1][i]);
}
cout << ans << '\n';
}
