#include <bits/stdc++.h>
using namespace std;
#define int long long
#define m_p make_pair
#define t_s to_string
#define t_ll stoll
#define B break;
#define C continue;
#define R(x) return x;
#define K exit(0);
#define W while
#define F for
#define E else 
#define I if
#define EI else if
#define G(x) x=rd();
#define P printf
#define __lcm(a,b) (a/__gcd(a,b)*b)
#define X INT_MAX
#define N INT_MIN
int rd(){
	int x=0,f=1,ch=getchar();
	W(ch<'0'||ch>'9'){
		I(ch=='-') f=-1;
		ch=getchar();
	}
	W(ch>='0'&&ch<='9') x=(x<<1)+(x<<3)+(ch^48),ch=getchar();
	R(x*f)
}
int arr[long(2e6)],sm[long(2e6)],smallsm[long(2e6)];
signed main()
{
	int x,s=0,iszheng=0,mxfu=N;
	G(x)
	F(int i=1;i<=x;i++){arr[i]=rd(),s+=arr[i];I(arr[i]<0){mxfu=max(mxfu,arr[i]);}E{iszheng=1;}}
	smallsm[1]=arr[1];
	sm[1]=arr[1];
	F(int i=2;i<=x;i++){
		sm[i]=max(sm[i-1]+arr[i],arr[i]);
		smallsm[i] = min(smallsm[i-1]+arr[i],arr[i]);
	}
	int mx=N,mn=X;
	F(int i=1;i<=x;i++){
		mx=max(mx,sm[i]);
		mn=min(mn,smallsm[i]);
	}
	printf("%lld\n",(iszheng?max(s-mn,mx):mxfu));
	R(0)
}