#include <iostream>
#include<bits/stdc++.h>
using namespace std;
typedef long long int ll;

int main() {
     ll n;
     cin>>n;
     vector<ll>a;
     ll sum =0;
     for(ll i=0;i<n;i++){
         ll y;
         cin>>y;
         sum=sum+y; 
         a.push_back(y*-1);
     }
     // vector<ll>p(n,0); // for s2
     // for(ll i=1;i<=n-3;i++){
     //   p[i]=max(a[i],a[i]+p[i-1]);
     // } 
     vector<ll>s(n,0),smax(n,0);
     s[n-1]=a[n-1];
     smax[n-1]=a[n-1];
     for(ll i=n-2;i>=3;i--){
         s[i]=a[i]+s[i+1];
         smax[i]=max(s[i],smax[i+1]);
     }
      ll temp=-1e18;
      ll curr_sum=0,max_sum=INT_MIN;
      for(ll i=1;i<=n-3;i++){
          curr_sum=max(a[i],a[i]+curr_sum);
          max_sum=max(max_sum,curr_sum);
          ll s2=max_sum;
          ll s4=s[i+2];
          temp=max(temp, s2+s4);
      }
      ll final= sum-2*(-1*temp);
      cout<<final<<endl;
      return 0;
}