//header{{{
#pragma GCC optimize("Ofast")
#include <bits/stdc++.h>

#include <boost/sort/spreadsort/spreadsort.hpp>
#include <boost/multiprecision/cpp_int.hpp>
#include <boost/multiprecision/cpp_dec_float.hpp>
#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/dijkstra_shortest_paths.hpp>
//#include <boost/graph/graph_utility.hpp>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/tag_and_trait.hpp>
#include <ext/pb_ds/trie_policy.hpp>

using namespace __gnu_pbds;
using namespace std;
//using namespace boost::multiprecision;
//using namespace boost::math;

typedef boost::adjacency_list<boost::listS, boost::vecS, boost::undirectedS,
        boost::no_property, boost::property<boost::edge_weight_t, int> > Graph;

#define rep(i,n) for(int i=0;i<(n);++i)
#define reps(i,n) for(int i=1;i<=(n);++i)
#define all(x) (x).begin(),(x).end()
#define Fixed fixed << setprecision(12)
#define bsort boost::sort::spreadsort::spreadsort
#define int int_fast64_t
using pii = pair<int,int>;

constexpr int INF  = 0x3f3f3f3f;
constexpr long long LINF = 0x3f3f3f3f3f3f3f3fLL;
constexpr int mod1 = 1e9+7; 
constexpr int mod2 = 998244353;
template <class Func>

class FixPoint : Func {
public:
    explicit constexpr FixPoint(Func&& f) noexcept : Func(forward<Func>(f)) {}
 
    template <class... Args>
    constexpr decltype(auto) operator()(Args&&... args) const {
        return Func::operator()(*this, std::forward<Args>(args)...);
    }
};
 
template <class Func>
static inline constexpr decltype(auto) makeFixPoint(Func&& f) noexcept {
    return FixPoint<Func>{forward<Func>(f)};
}

template <class A, class B> inline bool chmax(A &a, const B &b) { return b > a && (a = b, true); }
template <class A, class B> inline bool chmin(A &a, const B &b) { return b < a && (a = b, true); }

template <class T> using min_heap = priority_queue<T,vector<T>,greater<T> >;
template <class T> using max_heap = priority_queue<T>;
template <class A, class B> using umap = unordered_map<A,B>;

template <typename T> using Set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template <typename K, typename V> using Umap = gp_hash_table<K, V>;
using Trie = trie<string, null_type, trie_string_access_traits<>, pat_trie_tag, trie_prefix_search_node_update>;
  
inline int square(int a){ return a * a;}
inline int updiv(int a,int b){ return (a + b - 1) / b; }

constexpr int dx[] = {1,0,-1,0,1,1,-1,-1};
constexpr int dy[] = {0,-1,0,1,1,-1,-1,1};

constexpr int dxw[] = {-2, -1, 0, 1, 2, -2, -1, 1, 2, -2, 2, -2, -1, 1, 2, -2, -1, 0, 1, -2};
constexpr int dyw[] = {-2, -2, -2, -2, -2, -1, -1, -1, -1, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 2};

struct negrightshift {
    inline int operator() (const int &x, const unsigned offset) {
        return -(x >> offset);
    }
};
//}}}


signed main(){
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);
    cout.setf(ios_base::fixed);
    cout.precision(10);

    int n;
    cin >> n;

    vector<int> a(n+1);

    reps(i,n){
        cin >> a[i];
        a[i] += a[i-1];
    }

    auto sum = [&](int L, int R){
        return (a[R] - a[L - 1]);
    };

    // X[L, point],Y(point, R]
    auto BinSerch = [&](int L, int R){
        int l = L, r = R; 
        while(r - l > 1){
            int mid = (r + l) / 2;
            if(sum(L, mid) <= sum(mid + 1, R)){
                l = mid; 
            }else{
                r = mid;
            }
        }
        return (l);
    };

    int res = LINF;

    // B[1, lp], C(lp, mid], D(mid, rp], E(rp, n]
    for(int mid = 2; mid <= n - 2; ++mid){
        int lp = BinSerch(1, mid);
        int rp = BinSerch(mid + 1, n);
        rep(i,2){
            rep(j,2){
                if(lp + i == mid || rp + j == n) continue;
                int B = sum(1, lp + i);
                int C = sum(lp + i + 1, mid);
                int D = sum(mid + 1, rp + j);
                int E = sum(rp + j + 1, n);
                chmin(res, max({B, C, D, E}) - min({B, C, D, E}));
            }
        }
    }

    cout << res << '\n';

    return 0;
}

Measured memory_bytes: 4756