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#include <bits/stdc++.h>
#define FOR(i, n) for(int i = 0; i < (n); ++i)
#define REP(i, a, b) for(int i = (a); i < (b); ++i)
#define TRAV(i, a) for(auto & i : (a))
#define SZ(x) ((int)(x).size())
#define PR std::pair
#define MP std::make_pair
#define X first
#define Y second
typedef long long ll;
typedef std::pair<int, int> PII;
typedef std::vector<int> VI;

const ll INF = 1000000666*1000000000ll;

int main(){
	std::ios_base::sync_with_stdio(false);
	std::cin.tie(0);

	int n;
	std::cin >> n;
	VI A(n);
	FOR(i, n) std::cin >> A[i];

	std::set<PR<ll, int> > set;

	set.insert(MP(0ll, n));

	ll pref = 0;
	int ans = -1;

	FOR(i, n){
		ll a = A[i];
		pref += a;

		auto it = set.upper_bound(MP(pref, 1000000000));
		if(it == set.begin()) continue;

		it--;
		int my = it->Y - (n-i);
		if(i == n-1){
			ans = my;
		}
		it = set.insert(MP(pref, my + (n-1-i))).X;
		if(it != set.begin() && std::prev(it)->Y <= it->Y){
			set.erase(it);
			continue;
		}
		while(true){
			auto nxt = std::next(it);
			if(nxt == set.end()) break;
			if(nxt->Y >= it->Y) set.erase(nxt);
			else break;
		}
	}

	std::cout << ans << "\n";

	return 0;
}