italian_olympiad1

#include <cstdio>
#include <vector>
#include <algorithm>
#include <cmath>
#define MAXN 505
using namespace std;

int N;
vector <int> A;

int main(){
    //freopen("italian1.in","r",stdin);
    scanf("%d\n",&N);
    for(int i=0;i<N;i++){
        int a; scanf("%d",&a);
        A.push_back(a);
    }
    int lmin = 0;
    while(A.size() >= 2){
        /* Prints array that is being iterated through */
        //for(int i=0;i<A.size();i++)printf("%d ",A[i]); printf("\n");

        int minval = INT_MAX-(1<<10), absmin = INT_MAX-(1<<10), minidx = 0;
        for(int i=0;i<A.size()-1;i++){
            int cval = A[i] + A[i+1];
            if(abs(cval) < absmin){
                minval = cval;
                absmin = abs(cval);
                minidx = i;
            }
        }
        lmin = max(lmin,abs(absmin));
        int c = 0;
        for(int i=0;i<A.size();i++){
            if(i == minidx){
                A[c++] = minval;
                i++;
                continue;
            }
            A[c++] = A[i];
        }
        int x = A.size(); A.resize(x-1);
    }
    printf("%d\n",lmin);
    return 0;
}