#include <bits/stdc++.h>
using namespace std; 
#define ll long long
#define pb push_back

//kalo mines semua?
//-50 -4 -26 - 42
//-50 - (-4 - 26 - 42)

int main()
{
	int n; 
	cin >> n; 
	int a[n + 5]; 
	ll res = 0;
	ll ares = 0; 
	ll semua = 0; 
	for(int i = 1; i <= n; i++)
	{
		cin >> a[i];
		semua += a[i];
	}
	
	int l = 1;
	int r = 1;
	int ml = 1; 
	int mr = 1; 
	ll sum = 0; 
	for(int i = 1; i <= n; i++)
	{
		if(sum + a[i] >= 0)
		{
			sum += a[i];
//			if(l == r)
//			{
//				l = i; r = i;
//			}
			r = i; 
		}
		else
		{
			sum = 0; 
			l = i;
			r = i; 
		}
		if(sum > res)
		{
			res = sum; 
			ml = l;
			mr = r; 
		}
//		cout<<i<<": "<<sum<<"\n";
	}
	
	if(res == 0)
	{
		res = max(abs(semua - a[1]), abs(semua - a[n]));
		ares = max(ares, res); 
	}
	else if(ml == 1 && mr == n)
	{
//		cout << res << endl; 
		res = max(abs(semua - a[1] - a[1]), abs(semua - a[n] - a[n]));
		ares = max(ares, res); 
	}
	else
	{
		ll minim = 0;  
		ll sum = 0; 
		for(int i = 1; i < ml; i++)
		{
			if(sum + a[i] > 0)
			{
				sum = 0; 
			}
			else
			{
				sum += a[i];
			}
			
			minim = min(minim, sum); 
		}
	    sum = 0; 
		for(int i = mr + 1; i <= n; i++)
		{
			if(sum + a[i] > 0)
			{
				sum = 0; 
			}
			else
			{
				sum += a[i];
			}
			
			minim = min(minim, sum); 
		}
		res = abs(res - minim); 
		ares = max(ares, res); 
	}
	
    l = 1;
	r = 1;
	ml = 1; 
	mr = 1; 
	sum = 0; 
	ll minim = 1e18; 
	for(int i = 1; i <= n; i++)
	{
		if(sum + a[i] < 0)
		{
			sum += a[i];
			if(l == r)
			{
				l = i; r = i;
			}
			r = i; 
		}
		else
		{
			sum = 0; 
			l = i;
			r = i; 
		}
		if(sum < minim)
		{
//			cout << l << " " << r << endl; 
			minim = sum; 
			ml = l;
			mr = r; 
		}
	}
//	cout << ml << " " << mr << endl; 
	
	if(minim < 0)
	{
		sum = 0;
		ll tambah = 0; 
		for(int j = 1; j < ml; j++)
		{
			if(sum + a[j] < 0)
			{
				sum = 0; 
			}
			else
			{
				sum += a[j];
			}
			tambah = max(tambah, sum); 
		}

	    sum = 0; 
		for(int i = mr + 1; i <= n; i++)
		{
			if(sum + a[i] < 0)
			{
				sum = 0; 
			}
			else
			{
				sum += a[i];
			}
			
			tambah = max(tambah, sum);
		}
		res = abs(tambah - minim); 
		ares = max(ares, res); 
	}
	
	cout << res << endl; 
	return 0; 
}