#include <iostream>
using namespace std;
int N, A[5001];
int cst[5001][5001], DP[5001][5001], pref[5001], suf[5001];
int main()
{
cin >> N;
for (int i = 0; i < N; i++) cin >> A[i];
for (int i = 0; i < N; i++)
{
int sumL = 0, sumR = 0, l = i - 1, r = i;
while (l >= 0 && r < N)
{
if (sumL + A[l] < sumR + A[r]) {sumL += A[l--];}
else {sumR += A[r++];}
if (l >= 0 && r < N && sumL == sumR) {cst[i][l] = 1; cst[i][r] = 1;}
}
for (int j = i + 1; j < N; j++) cst[i][j] = cst[i][j - 1] + cst[i][j];
for (int j = i - 2; j >= 0; j--) cst[i][j] = cst[i][j + 1] + cst[i][j];
}
for (int i = 0; i < N; i++)
{
if (i)
{
for (int j = 0; j < i; j++)
{
pref[j] = DP[j][i - 1];
if (j) pref[j] = max(pref[j - 1], pref[j]);
}
for (int j = i - 1; j >= 0; j--)
{
suf[j] = DP[j][i - 1] + cst[i][j];
if (j + 1 < i - 1) suf[j] = max(suf[j + 1], suf[j]);
}
}
int k = i - 1;
for (int j = i; j < N; j++)
{
while (k >= 0 && cst[i][k] <= cst[i][j]) {k--;}
if (k + 1 < i) DP[i][j] = suf[k + 1];
if (k >= 0) DP[i][j] = max(DP[i][j], pref[k] + cst[i][j]);
}
}
/*for (int i = 0; i < N; i++)
{
for (int j = i; j < N; j++)
{
cerr << DP[i][j] << " ";
}
cerr << "\n";
}*/
int res = 0;
for (int i = 0; i < N; i++) {res = max(res, DP[i][N - 1]);}
cout << res << "\n";
return 0;
}
