#ifndef _GLIBCXX_NO_ASSERT
#include <cassert>
#endif
#include <cctype>
#include <cerrno>
#include <cfloat>
#include <ciso646>
#include <climits>
#include <clocale>
#include <cmath>
#include <csetjmp>
#include <csignal>
#include <cstdarg>
#include <cstddef>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>

#if __cplusplus >= 201103L
#include <ccomplex>
#include <cfenv>
#include <cinttypes>
#include <cstdbool>
#include <cstdint>
#include <ctgmath>
#include <cwchar>
#include <cwctype>
#endif

// C++
#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <exception>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iosfwd>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <locale>
#include <map>
#include <memory>
#include <new>
#include <numeric>
#include <ostream>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdexcept>
#include <streambuf>
#include <string>
#include <typeinfo>
#include <utility>
#include <valarray>
#include <vector>

#if __cplusplus >= 201103L
#include <array>
#include <atomic>
#include <chrono>
#include <condition_variable>
#include <forward_list>
#include <future>
#include <initializer_list>
#include <mutex>
#include <random>
#include <ratio>
#include <regex>
#include <scoped_allocator>
#include <system_error>
#include <thread>
#include <tuple>
#include <typeindex>
#include <type_traits>
#include <unordered_map>
#include <unordered_set>
#endif
using namespace std;

#define ll long long
//typedef pair<int,int> Pint;
//typedef pair<ll, ll> P;
//typedef pair<int, pair<int, int>> P;
//typedef tuple<int,int,int> T;
typedef vector<ll> vec;
typedef vector<vec> mat;
#define rep(i, n) for(ll i = 0; i < n; i++)
#define revrep(i, n) for(ll i = n-1; i >= 0; i--)
ll max(ll a, ll b){return (a > b) ? a : b;}
ll min(ll a, ll b){return (a < b) ? a : b;}
ll Mypow(ll x, ll k){
  ll res = 1;
  while(k > 0){
    if(k % 2) res *= x;
    x *= x;
    k /= 2;
  }
  return res;
}


ll INFL = 1LL << 60;//10^18 = 2^60
int INF = 1 << 30;//10^9
ll MOD  = 1000000007;
//vector<int> dy = {0,0,1,-1,};
//vector<int> dx = {1,-1,0,0};
//vector<int> dy = {0, 1, 1, 1, 0, -1, -1, -1, 0};
//vector<int> dx = {0, 1, 0, -1, -1, -1, 0, 1, 1};

ll N;
vector<ll> A;

ll P, Q, R, S;

ll sa(){
  vector<ll> vec(4);
  vec[0] = P, vec[1] = Q, vec[2] = R, vec[3] = S;
  sort(vec.begin(), vec.end());
  return vec[3] - vec[0];
}

int main(){
  //aa|aaaaaaa
  //aaaaaaa|aa
  //aaaaa
  cin >> N;
  A.resize(N); rep(i, N) cin >> A[i];
  ll s = 0, t = -1;
  P = A[0];
  Q = A[1];
  ll sum[N-1];
  sum[0] = 0;
  ll ss = 0;
  for(int i = 1; i < N-1; i++){
    sum[i] = sum[i-1] + A[i+1];
    ss += A[i+1];
  }
  ll m = INFL;
  for(int i = 2; i < N-1; i++){
    if(m > abs(ss-2*sum[i-1])){
      m = abs(ss-2*sum[i-1]);
      t = i;
    }
  }
  R = sum[t-1];
  S = ss - sum[t-1];
  ll ans = sa();
  for(int i = 2; i < N-2; i++){
    Q += A[i];
    //sとtを動かす
    //s < i
    //sを動かす
    while(s < i-1){
      if(abs((P+A[s+1]) - (Q-A[s+1])) < abs(P-Q)){
        P += A[s+1];
        Q -= A[s+1];
        s++;
      }else break;
    }
    //tを動かす
    R -= A[i];
    if(i == t){
      t++;
      R += A[t];
      S -= A[t];
    }
    while(t < N - 1){
      if(abs((R+A[t+1]) - (S-A[t+1])) < abs(R - S)){
        R += A[t+1];
        S -= A[t+1];
        t++;
      }else break;
    }
    ans = min(ans, sa());
  }
  cout << ans << endl;
}


Measured memory_bytes: 3328