C++ :

#include<bits/stdc++.h>
using namespace std;
int a,b[1000005],s,ss;
int main()
{
	cin>>a;
	for (int i=0;i<a;i++)
		cin>>b[i];
	for(int i=0;i<a;i++)
	{
		s+=b[i];
		if(s<0)
		{
			ss+=s*-1;
			s+=s*-1;
		}
	}
	cout<<ss;
	return 0;
}