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

int a[400005];
int b[400005];
signed main() {
	int n,maxn=0,minn=2e9;cin>>n;
	b[0]=0;
	for(int i=1; i<=n; i++) {
		cin>>a[i];
		b[i]=b[i-1]+a[i];
	}
	for(int i=1; i<=n; i++) {
		maxn=max(maxn,b[i]-minn);
		minn=min(minn,b[i]);
	}
	cout<<maxn;
	return 0;
}