ソースコード
#include "bits/stdc++.h"
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
#define FOR(i, s, e) for (ll(i) = (s); (i) < (e); (i)++)
#define FORR(i, s, e) for (ll(i) = (s); (i) > (e); (i)--)
#define debug(x) cout << #x << ": " << x << endl
#define mp make_pair
#define pb push_back
const ll MOD = 1000000007;
const int INF = 1e9;
const ll LINF = 1e16;
const double PI = acos(-1.0);
int dx[8] = {0, 0, 1, -1, 1, 1, -1, -1};
int dy[8] = {1, -1, 0, 0, 1, -1, 1, -1};
/* ----- xtimex Problem: __CONTEST_NAME__ / Link: ----- */
/* ------問題------
-----問題ここまで----- */
/* -----解説等-----
----解説ここまで---- */
ll N;
ll a[100005];
ll sum[100005];
ll ans = 0LL;
int main() {
cin.tie(0);
ios_base::sync_with_stdio(false);
cin >> N;
FOR(i, 0, N) {
cin >> a[i];
sum[i + 1] = sum[i] + a[i];
}
FOR(i, 1, N+1) {
ll l = sum[i];
ll r = sum[N]-sum[i];
if (l >= 0)ans = max(ans, i);
if (r >= 0)ans = max(ans, N-i);
}
if (ans == 0)ans = -1;
cout << ans << endl;
return 0;
}