#include <bits/stdc++.h>
int main() {
int N;
std::cin >> N;
std::vector<int> D(N);
for (auto &e : D) {
std::cin >> e;
}
std::vector<std::vector<int>> dp(N, std::vector<int>(N));
for (int s = 1; s < N; ++s) {
std::vector<int> a, b;
for (int i = s; i < N; ++i) {
a.push_back(D[i]);
if (i != s) {
a[i - s] += a[i - s - 1];
}
}
for (int i = 0; i < s; ++i) {
b.push_back(D[s - i - 1]);
if (i != 0) {
b[i] += b[i - 1];
}
}
const int t = (int)a.size();
std::vector<int> points;
{
int r = 0;
for (int i = 0; i < t - 1; ++i) {
while (r != s and b[r] < a[i]) {
++r;
}
if (r < s - 1 and a[i] == b[r]) {
points.push_back(a[i]);
}
}
}
const int m = (int)points.size();
std::vector<int> max_c(s);
for (int i = 0; i < s; ++i) {
max_c[i] = dp[s - 1][i];
if (i != 0) {
max_c[i] = std::max(max_c[i], max_c[i - 1]);
}
}
int max_v = 0;
dp[s][s] = max_c[s - 1];
int r = 0, count_p = 0;
for (int i = 1; i < t; ++i) {
// dp[s + i][s]
while (count_p != m and points[count_p] <= a[i - 1]) {
while (r != s - 1 and b[r] < points[count_p]) {
max_v = std::max(max_v, dp[s - 1][s - r - 2] + count_p);
++r;
}
++count_p;
}
dp[s + i][s] = std::max(max_v, r == s - 1 ? 0 : (max_c[s - r - 2] + count_p));
/*
for (int j = 0; j < s - 1; ++j) {
int v = dp[s - 1][j];
auto itr = std::upper_bound(points.begin(), points.end(), std::min(a[i - 1], b[s - j - 2]));
dp[s + i][s] = std::max(dp[s + i][s], v + (int)(itr - points.begin()));
}
*/
}
}
std::cout << *std::max_element(dp[N - 1].begin(), dp[N - 1].end()) << std::endl;
}
