#include #include using namespace std; using namespace atcoder; typedef long long int ll; typedef long double ld; typedef vector vi; typedef vector vl; typedef vector vvl; typedef vector vvvl; typedef vector vvvvl; typedef vector vb; typedef vector vvb; typedef vector vvvb; typedef vector vvvvb; typedef pair pl; typedef pair ppl; typedef pair pppl; typedef pair pppppl; #define rep(i,a,b) for(int i=(a);i<(b);i++) #define rrep(i,a,b) for(int i=(b)-1;i>=(a);i--) #define all(a) begin(a),end(a) #define sz(a) (int)(a).size() #define F first #define S second #define bs(A,x) binary_search(all(A),x) #define lb(A,x) (ll)(lower_bound(all(A),x)-A.begin()) #define ub(A,x) (ll)(upper_bound(all(A),x)-A.begin()) #define cou(A,x) (ll)upper_bound(all(A),x)-lower_bound(all(A),x)) templateusing min_priority_queue=priority_queue,greater>; templatebool chmax(T&a,T b){if(abool chmin(T&a,T b){if(b vm; typedef vector vvm; typedef vector vvvm; typedef vector vvvvm; ostream&operator<<(ostream&os,mint a){os<>(istream&is,mint&a){int x;is>>x;a=mint(x);return is;} //*/ templateostream&operator<<(ostream&os,pairp){os<istream&operator>>(istream&is,pair&p){is>>p.F>>p.S;return is;} templateostream&operator<<(ostream&os,vectorv){rep(i,0,sz(v))os<istream&operator>>(istream&is,vector&v){for(T&in:v)is>>in;return is;} int main(){ cin.tie(0)->sync_with_stdio(0); cin.exceptions(cin.failbit); ll N;cin>>N; vl A(N);cin>>A; vl B(N+1); rep(i,0,N)B[i+1]=A[i]+B[i]; vl ma1(N+1,-1e18),mi1(N+1,1e18),ma2(N+1,-1e18),mi2(N+1,1e18); for(ll i=0,ma=-1e18,mi=1e18;i=0;i--){ chmax(ma,B[i+1]); chmin(mi,B[i+1]); chmax(ma2[i],ma2[i+1]); chmax(ma2[i],ma-B[i]); chmin(mi2[i],mi2[i+1]); chmin(mi2[i],mi-B[i]); } ll ans=-1e18; rep(i,1,N){ chmax(ans,ma1[i]*ma2[i]); chmax(ans,ma1[i]*mi2[i]); chmax(ans,mi1[i]*ma2[i]); chmax(ans,mi1[i]*mi2[i]); } cout<