#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <string>
#include <vector>
#include <list>
#include <map>
#include <iostream>
#include <queue>
#include <stack>
#include <algorithm>
#include <deque>
#include <fstream>
#include <functional>
#include <cctype>
#include <unordered_set>
#include <unordered_map>

using namespace std;

#define pb push_back
#define mp make_pair
#define rep(i,n) for(int i = 0; i < (n); i++)
#define repr(i,b,e) for(int i = (b); i <= (e); i++)

#define pr(x) do{cerr << (#x) << " = " << (x) << endl;}while(0)
#define pri(x,i) do{cerr << (#x) << "[" << i << "] = " << (x[i]) << endl;}while(0)
#define UNIQUE(v) do{ (v).erase( unique(begin(v), end(v)), end(v) ); } while(0)

namespace std {
	template<class S, class T> pair<S, T> operator + (const pair<S, T> &a, const pair<S, T> &b) {return mp<S, T>(a.first + b.first, a.second + b.second);}
	template<class S, class T> pair<S, T> operator - (const pair<S, T> &a, const pair<S, T> &b) {return mp<S, T>(a.first - b.first, a.second - b.second);}
	template<class S, class T> pair<S, T>& operator += (pair<S, T> &a, const pair<S, T> &other) {return a = a + other;}
	template<class S, class T> pair<S, T>& operator -= (pair<S, T> &a, const pair<S, T> &other) {return a = a - other;}
	template<class S, class T> ostream& operator << (ostream& ost, pair<S, T> p) {ost << "(" << p.first << ", " << p.second << ")";return ost;}
	template<class T> ostream& print_iterable_container(ostream& ost, T& container) {
		for (auto&& iter = begin(container); iter != end(container); ++iter) ost << (iter == begin(container) ? " [ " : ", ") << (*iter);
		return ost << " ]";
	}
#	define APPLY_PRINT_ITERABLE_CONTAINER(container_type)\
	template<class T> ostream& operator << (ostream& ost, container_type<T>& container) {\
		return print_iterable_container(ost, container);\
	}
	APPLY_PRINT_ITERABLE_CONTAINER(vector);
	APPLY_PRINT_ITERABLE_CONTAINER(list);
	APPLY_PRINT_ITERABLE_CONTAINER(deque);
}

template<class T> inline bool CHMAX(T &l,const T &r){return l<r?l=r,1:0;}
template<class T> inline bool CHMIN(T &l,const T &r){return l>r?l=r,1:0;}

using ll = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using vi = vector<int>;
using vll = vector<ll>;
using vvi = vector<vi>;
using vvll = vector<vll>;
using vpii = vector<pii>;
using vpll = vector<pll>;

using ld = long double;

template<class T> using VV = vector<vector<T> >;
template<class T> using maxPQ = priority_queue<T>;
template<class T> using minPQ = priority_queue<T, vector<T>, greater<T> >;
template<class T, class U> using uomap = unordered_map<T, U>;
template<class T> using uoset = unordered_set<T>;

const ll INF = 1001001001;
const ll INFll = (ll)INF * INF;
const ll MOD = 1000000007;
const ll MOD_FFT = 998244353;
const ld EPS = 1e-15;

//function<void(int,int)> tensi_no_3p=[&](int v,int d){
//};

pll check(vll &v, int leftmost, int rightmost) {
	if (rightmost - leftmost < 2) return mp(-1, -1);
	int left = leftmost, right = rightmost;
	ll ans = INFll;
	pll ret = mp(0, 0);
	while (right - left > 1) {
		int middle = (left + right) / 2;
		ll sl = v[middle] - v[leftmost];
		ll sr = v[rightmost] - v[middle];
		if (abs(sl - sr) < ans) {
			ans = abs(sl - sr);
			ret = mp(sl, sr);
		}
		if (sl > sr) right = middle;
		else left = middle;
	}
	if (ret.second < ret.first) swap(ret.first, ret.second);
	return ret;
}

int main() {
	ios_base::sync_with_stdio(false);
	int N; cin >> N;
	vll A(N);
	rep(i, N) cin >> A[i];
	vll C(N + 1);
	rep(i, N) C[i + 1] = C[i] + A[i];
	ll left = -1, right = INFll;
	pr(C);
	while (right - left > 1) {
		ll middle = (left + right) / 2;
		bool ok = false;
		rep(i, N + 1) {
			pll cl = check(C, 0, i);
			pll cr = check(C, i, N);
			if (cl.first == -1 || cr.first == -1) continue;
			ll cmin = min(cl.first, cr.first);
			ll cmax = max(cl.second, cr.second);
			if (cmax - cmin <= middle) {
				ok = true;
				break;
			}
		}

		if (ok) {
			right = middle;
		}
		else {
			left = middle;
		}
	}
	cout << right << endl;
	return 0;
}


Measured memory_bytes: 3456