#include <bits/stdc++.h>
#define whlie while
#define pb push_back
#define eb emplace_back
#define fi first
#define se second
#define rep(i,N) for(int i = 0; i < (N); i++)
#define repr(i,N) for(int i = (N) - 1; i >= 0; i--)
#define rep1(i,N) for(int i = 1; i <= (N) ; i++)
#define repr1(i,N) for(int i = (N) ; i > 0 ; i--)
#define each(x,v) for(auto& x : v)
#define all(v) (v).begin(),(v).end()
#define sz(v) ((int)(v).size())
#define ini(...) int __VA_ARGS__; in(__VA_ARGS__)
#define inl(...) ll __VA_ARGS__; in(__VA_ARGS__)
#define ins(...) string __VA_ARGS__; in(__VA_ARGS__)
using namespace std; void solve();
using ll = long long; using vl = vector<ll>;
using vi = vector<int>; using vvi = vector< vector<int> >;
constexpr int inf = 1001001001;
constexpr ll infLL = (1LL << 61) - 1;
struct IoSetupNya {IoSetupNya() { cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(15); cerr << fixed << setprecision(7);} } iosetupnya;
template<typename T, typename U> inline bool amin(T &x, U y) { return (y < x) ? (x = y, true) : false; }
template<typename T, typename U> inline bool amax(T &x, U y) { return (x < y) ? (x = y, true) : false; }
template<typename T, typename U> ostream& operator <<(ostream& os, const pair<T, U> &p) { os << p.first << " " << p.second; return os; }
template<typename T, typename U> istream& operator >>(istream& is, pair<T, U> &p) { is >> p.first >> p.second; return is; }
template<typename T> ostream& operator <<(ostream& os, const vector<T> &v) { int s = (int)v.size(); rep(i,s) os << (i ? " " : "") << v[i]; return os; }
template<typename T> istream& operator >>(istream& is, vector<T> &v) { for(auto &x : v) is >> x; return is; }
void in(){} template <typename T,class... U> void in(T &t,U &...u){ cin >> t; in(u...);}
void out(){cout << "\n";} template <typename T,class... U> void out(const T &t,const U &...u){ cout << t; if(sizeof...(u)) cout << " "; out(u...);}
template<typename T>void die(T x){out(x); exit(0);}
#ifdef NyaanDebug
  #include "NyaanDebug.h"
  #define trc(...) do { cerr << #__VA_ARGS__ << " = "; dbg_out(__VA_ARGS__);} while(0)
  #define trca(v,N) do { cerr << #v << " = "; array_out(v , N);cout << endl;} while(0)
#else
  #define trc(...)
  #define trca(...)
  int main(){solve();}
#endif
using P = pair<ll,ll>; using vp = vector<P>;
constexpr int MOD = /**/ 1000000007; //*/ 998244353;
/////////

void solve(){
  ini(N);
  vl a(N); in(a);

  vl rui(N + 1 , 0);
  rep(i , N) rui[i + 1] = rui[i] + a[i];

  auto q = [&](int l,int r)->ll{return rui[r] - rui[l];};

  //　ある区間を二等分すると？
  auto f = [&](int l,int r) -> P{
    ll s = q(l , r);
    auto it = upper_bound(begin(rui) + l , begin(rui) + r , s / 2 + rui[l]);
    if(it == begin(rui) + l) return P(s - *it + rui[l] , *it - rui[l]);
    if(it == begin(rui) + r) return P(s - *(it - 1) + rui[l], *(it - 1) - rui[l]);
    P a = P(s - *it + rui[l], *it - rui[l]) , b = P(s - *(it - 1) + rui[l], *(it - 1) - rui[l]);
    return abs(a.fi - a.se) < abs(b.fi - b.se) ? a : b;
  };

  // 答えを返す関数
  auto g = [&](P a,P b){
    vl v ({a.fi , a.se , b.fi , b.se});
    sort(all(v));
    return v.back() - *begin(v);
  };

  ll ans = infLL;
  // 分断位置は[0, i) [i , N)とする
  rep1(i , N - 1){
    auto l = f(0 , i) , r = f(i , N);
    amin(ans , g(l , r) );
    trc( i , l , r , g(l , r));
  }

  out(ans);

}

Measured memory_bytes: 3328