#include <bits/stdc++.h>
#include <sys/time.h>
using namespace std;

// hamko utils
#define rep(i,n) for(long long i = 0; i < (long long)(n); i++)
#define repi(i,a,b) for(long long i = (long long)(a); i < (long long)(b); i++)
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define fi first
#define se second
#define mt make_tuple
#define mp make_pair
template<class T1, class T2> bool chmin(T1 &a, T2 b) { return b < a && (a = b, true); }
template<class T1, class T2> bool chmax(T1 &a, T2 b) { return a < b && (a = b, true); }

using ll = long long; using vll = vector<ll>; using vvll = vector<vll>; using P = pair<ll, ll>;
using ld = long double;  using vld = vector<ld>; 
using vi = vector<int>; using vvi = vector<vi>; vll conv(vi& v) { vll r(v.size()); rep(i, v.size()) r[i] = v[i]; return r; }

inline void input(int &v){ v=0;char c=0;int p=1; while(c<'0' || c>'9'){if(c=='-')p=-1;c=getchar();} while(c>='0' && c<='9'){v=(v<<3)+(v<<1)+c-'0';c=getchar();} v*=p; } // これを使うならば、tieとかを消して！！
template <typename T, typename U> ostream &operator<<(ostream &o, const pair<T, U> &v) {  o << "(" << v.first << ", " << v.second << ")"; return o; }
template<size_t...> struct seq{}; template<size_t N, size_t... Is> struct gen_seq : gen_seq<N-1, N-1, Is...>{}; template<size_t... Is> struct gen_seq<0, Is...> : seq<Is...>{};
template<class Ch, class Tr, class Tuple, size_t... Is>
void print_tuple(basic_ostream<Ch,Tr>& os, Tuple const& t, seq<Is...>){ using s = int[]; (void)s{0, (void(os << (Is == 0? "" : ", ") << get<Is>(t)), 0)...}; }
template<class Ch, class Tr, class... Args> 
auto operator<<(basic_ostream<Ch, Tr>& os, tuple<Args...> const& t) -> basic_ostream<Ch, Tr>& { os << "("; print_tuple(os, t, gen_seq<sizeof...(Args)>()); return os << ")"; }
ostream &operator<<(ostream &o, const vvll &v) { rep(i, v.size()) { rep(j, v[i].size()) o << v[i][j] << " "; o << endl; } return o; }
template <typename T> ostream &operator<<(ostream &o, const vector<T> &v) { o << '['; rep(i, v.size()) o << v[i] << (i != v.size()-1 ? ", " : ""); o << "]";  return o; }
template <typename T> ostream &operator<<(ostream &o, const deque<T> &v) { o << '['; rep(i, v.size()) o << v[i] << (i != v.size()-1 ? ", " : ""); o << "]";  return o; }
template <typename T>  ostream &operator<<(ostream &o, const set<T> &m) { o << '['; for (auto it = m.begin(); it != m.end(); it++) o << *it << (next(it) != m.end() ? ", " : ""); o << "]";  return o; }
template <typename T>  ostream &operator<<(ostream &o, const unordered_set<T> &m) { o << '['; for (auto it = m.begin(); it != m.end(); it++) o << *it << (next(it) != m.end() ? ", " : ""); o << "]";  return o; }
template <typename T, typename U>  ostream &operator<<(ostream &o, const map<T, U> &m) { o << '['; for (auto it = m.begin(); it != m.end(); it++) o << *it << (next(it) != m.end() ? ", " : ""); o << "]";  return o; }
template <typename T, typename U, typename V>  ostream &operator<<(ostream &o, const unordered_map<T, U, V> &m) { o << '['; for (auto it = m.begin(); it != m.end(); it++) o << *it; o << "]";  return o; }
vector<int> range(const int x, const int y) { vector<int> v(y - x + 1); iota(v.begin(), v.end(), x); return v; }
template <typename T> istream& operator>>(istream& i, vector<T>& o) { rep(j, o.size()) i >> o[j]; return i;}
template <typename T, typename S, typename U> ostream &operator<<(ostream &o, const priority_queue<T, S, U> &v) { auto tmp = v; while (tmp.size()) { auto x = tmp.top(); tmp.pop(); o << x << " ";} return o; }
template <typename T> ostream &operator<<(ostream &o, const queue<T> &v) { auto tmp = v; while (tmp.size()) { auto x = tmp.front(); tmp.pop(); o << x << " ";} return o; }
template <typename T> ostream &operator<<(ostream &o, const stack<T> &v) { auto tmp = v; while (tmp.size()) { auto x = tmp.top(); tmp.pop(); o << x << " ";} return o; }
template <typename T> unordered_map<T, ll> counter(vector<T> vec){unordered_map<T, ll> ret; for (auto&& x : vec) ret[x]++; return ret;};
string substr(string s, P x) {return s.substr(x.fi, x.se - x.fi); }
void vizGraph(vvll& g, int mode = 0, string filename = "out.png") { ofstream ofs("./out.dot"); ofs << "digraph graph_name {" << endl; set<P> memo; rep(i, g.size())  rep(j, g[i].size()) { if (mode && (memo.count(P(i, g[i][j])) || memo.count(P(g[i][j], i)))) continue; memo.insert(P(i, g[i][j])); ofs << "    " << i << " -> " << g[i][j] << (mode ? " [arrowhead = none]" : "")<< endl;  } ofs << "}" << endl; ofs.close(); system(((string)"dot -T png out.dot >" + filename).c_str()); }
size_t random_seed; namespace std { using argument_type = P; template<> struct hash<argument_type> { size_t operator()(argument_type const& x) const { size_t seed = random_seed; seed ^= hash<ll>{}(x.fi); seed ^= (hash<ll>{}(x.se) << 1); return seed; } }; }; // hash for various class
#define ldout fixed << setprecision(40) 

#define EPS (double)1e-14
#define INF (ll)1e18
#define mo  (ll)(1e9+7)
// end of hamko utils

int N, A[201010];
//---------------------------------------------------------------------------------------------------
ll B[201010]; //累積和
ll get(int L, int R) { // [L,R)
    if (L == R) return 0;
    ll res = B[R - 1];
    if (L) res -= B[L - 1]; //Lが0でない場合　resを[L,R)の区間累積和にする。Lが0のときは上の文章だけで区間累積和が出る
    return res;
}
//---------------------------------------------------------------------------------------------------
int main(int argc, char** argv) {
    cin >> N;
    for(int i=0;i<N;++i) cin >> A[i];
 
    B[0] = A[0];
    for(int i=1;i<N;++i) B[i] = B[i - 1] + A[i];
 
    ll ans = 1e9;
    // [0,a) [a,b) [b,c) [c,N)
    for(int b=2;b<N-1;++b){ //２つに分けるためのbを2からN-1まで全探索する
        int a, c;
        ll T, Q, R, S;
 
        {
            int ok = 0, ng = b;
            while (ok + 1 != ng) { //ok+1=ngになるまで繰り返す
                int md = (ng + ok) / 2;  //mdはngとokの真ん中
                if (get(0, md) < get(md, b)) ok = md;  //0からmdまでの区間累積和とmdからbまでの区間累積和を比較し後者が大きかったらokをmdの値に直す
                else ng = md;  //前者が大きかったり等しかったりしたらngをmdに直す
            }
            vector<int> v;
            if (ok) v.push_back(ok);  //okが0じゃなければvに入れる（ok=v[0]）
            if (ok + 1 != b) v.push_back(ok + 1);  //ok+1がbじゃなければok+1をvに入れる（ok+1=v[1])
            if (v.size() == 1) a = v[0]; //vの要素がokの分しかないならa=v[0]=ok
            else if (1 < v.size()) {
                int a0 = v[0], a1 = v[1]; //aはa0とa1どちらをとるべきか考える。絶対値の差が小さい方だ！
                if (abs(get(0, a0) - get(a0, b)) < abs(get(0, a1) - get(a1, b))) a = a0; 
                else a = a1;
            } else assert(0);  //ここに来たら死ぬ。vのサイズが0よりも小さかったらおかしいやろってことで殺す
        }
        
        {
            int ok = b, ng = N;  //bの後半でも同じことをする
            while (ok + 1 != ng) {
                int md = (ng + ok) / 2;
                if (get(b, md) < get(md, N)) ok = md;
                else ng = md;
            }
            vector<int> v;
            if (ok) v.push_back(ok);
            if (ok + 1 != N) v.push_back(ok + 1);
            if (v.size() == 1) c = v[0];
            else if (1 < v.size()) {
                int c0 = v[0], c1 = v[1];
                if (abs(get(b, c0) - get(c0, N)) < abs(get(b, c1) - get(c1, N))) c = c0;
                else c = c1;
            }
            else assert(0);
        }
 
        T = get(0, a);
        Q = get(a, b);
        R = get(b, c);
        S = get(c, N);
 
        ll mi = min(min(T, Q), min(R, S));
        ll ma = max(max(T, Q), max(R, S));
 
        chmin(ans, ma - mi);  //ma-miがansよりも小さかったらans=ma-miに更新してtrueを返す
    }
 
    cout << ans << endl;
}

Measured memory_bytes: 2560