#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;
}
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