#include<bits/stdc++.h>
#define ll long long
using namespace std;
vector<ll> a(100005);
int main(){
    int n;
    ll sum=0, total=0, ans=0;
    int l, r, ml, mr;
    cin>>n;
    for(int i=0; i<n; i++) cin>>a[i];
    l=r=0;
    ml=mr=-1;
    // largest positive maximum subarray
    for(int i=0; i<n; i++){
        if(sum + a[i] >= 0){
            sum+=a[i];
            r=i;
        }
        else{
            l=i+1;
            r=i+1;
            sum=0;
        }
        if(sum > total){
            total=sum;
            ml=l;
            mr=r;
        }
    }
    // cout<<"positive "<<ml<<" "<<mr<<": "<<total<<"\n";
    // hanya ada 1 grup
    if(ml == 0 && mr == (n-1)){
        ans=max(ans, max(abs(total-a[0]-a[0]), abs(total-a[n-1]-a[n-1])));
    }
    else if(ml != -1){
        // cari minimum kiri dan kanan
        ll sumleft=0, best=1e18;
        ll sumright=0;
        ml--;
        while(ml >= 0){
            sumleft+=a[ml];
            ml--;
            best=min(best, sumleft);
        }
        mr++;
        while(mr < n){
            sumright+=a[mr];
            mr++;
            best=min(best, sumright);
        }
        ans=max(ans, abs(total-best));
    }

    // largest negative
    sum=0;
    total=0;
    ml=mr=-1;
    r=l=0;
    for(int i=0; i<n; i++){
        if(sum + a[i] <= 0){
            sum+=a[i];
            r=i;
        }
        else{
            l=r=i+1;
            sum=0;
        }
        if(sum < total){
            total=sum;
            ml=l;
            mr=r;
        }
    }
    // cout<<"negative "<<ml<<" "<<mr<<": "<<total<<"\n";
    // hanya ada 1 grup
    if(ml == 0 && mr == (n-1)){
        ans=max(ans, max(abs(total-a[0]-a[0]), abs(total-a[n-1]-a[n-1])));
    }
    else if(ml != -1){
        // cari minimum kiri dan kanan
        ll sumleft=0, best=0;
        ll sumright=0;
        ml--;
        while(ml >= 0){
            sumleft+=a[ml];
            ml--;
            best=max(best, sumleft);
        }
        mr++;
        while(mr < n){
            sumright+=a[mr];
            mr++;
            best=max(best, sumright);
        }
        ans=max(ans, abs(total-best));
    }
    cout<<ans<<"\n";
}