#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <string>
#include <cmath>
#include <climits>
#include <algorithm>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <cassert>
#include <vector>
#define all(x) x.begin() , x.end()
#define fi first
#define se second
#define pb push_back
#define umax( x , y ) x = max( x , (y) )
#define umin( x , y ) x = min( x , (y) )
#define For( i , a ) for(int i=1;i<=a;i++)
#define ort (b+s)/2
#define y2 asrwjaelkf
#define y1 asseopirwjaelkf
#define set multiset

using namespace std;

inline int read() {
    int res = 0 ;int neg ;
    while(true){char ch = getchar();if(ch>='0' && ch<='9' || ch=='-'){if(ch=='-') neg = -1;else neg = 1 , res = ch-'0';break;} }
    while(true){char ch = getchar();if(ch>='0' && ch<='9') res*=10 , res+=ch-'0';else break;}
    return res*neg;
}

typedef long long Lint;
typedef double db;
typedef pair<Lint,Lint> ii;
typedef pair<db,db> dd;
typedef pair<dd,db> ddd;
typedef pair<int,ii> iii;
typedef pair<ii,ii> i4;

const int maxn = 500120;
const int maxm = 1000020;
const int MOd = 1e9 + 7;
const int K = 400;

int a, ar[maxn], n;
Lint p[maxn], g[maxn];
vector<ii> segment[maxn*3], st[maxn*3];

db inter( ii a, ii b ) {
    if( a.fi == b.fi ) {
        return -1e18;
        assert(0);
    }
    return (db)(a.se-b.se)/(b.fi-a.fi);
}

void add( vector<ii> &v, ii x ) {
    while( v.size() >= 2 && inter( v[v.size()-2], x ) <= inter( v[v.size()-2], v[v.size()-1] ) ) v.pop_back();
    v.pb( x );
}

Lint get( vector<ii> &v, Lint x ) {
    /*
    int l = 0, r = v.size()-2;
    while( l < r ) {
        int m = (l+2)/2;
        if( inter( v[m], v[m+1] ) )
    }*/
    int t = 0;
    for(int k=18;k>=0;k--)
        if( t+(1<<k) < v.size() && inter( v[t+(1<<k)-1], v[t+(1<<k)] ) <= x ) t += 1<<k;
    return v[t].fi*x + v[t].se;
}

Lint find( int l, int r, Lint x ) {
    Lint t = 0;
    for(l+=n, r+=n;l<=r;l=(l+1)>>1, r=(r-1)>>1) {
        if( l&1 ) umax( t, get( st[l], x ) );
        if( ~r&1 ) umax( t, get( st[r], x ) );
    }
    return t;
}

int main() {

    //freopen("asd.in","r",stdin);
    //freopen("out.txt","w",stdout);

    scanf("%d",&a);
    for(int i=1;i<=a;i++) scanf("%d",&ar[i]);

    for(int i=1;i<=a;i++)
        p[i] = p[i-1] + ar[i];

    for(int i=1;i<=a;i++)
        g[i] = g[i-1] + ar[i]*ar[i];

    n = 1;
    while( n <= a ) n <<= 1;

    for(int i=0;i<=a;i++) {
        for(int k=i+n;k;k>>=1)
            segment[k].pb( ii( -2*p[i], p[i]*p[i]+g[i] ) );
    }
    for(int i=1;i<n+n;i++) {
        sort( all( segment[i] ) );
        for(int j=0;j<segment[i].size();j++)
            add( st[i], segment[i][j] );
    }

    Lint ans = 0;
    for(int i=1;i<=a;i++) {
        Lint t = find( 0, i-1, p[i] );
        umax( ans, t+p[i]*p[i]-g[i] );
    }

    cout << ans/2 << endl;
    return 0;
}