B. Berland National Library-水题- Codeforces Round #Pi (Div. 2)

#include <cstdio>
#include <cmath>
#include <cstring>
#include <string>
#include <algorithm>
#include <iostream>
#include <queue>
#include <map>
#include <set>
#include <vector>
using namespace std;
 

__int64 vis[1000000+5];

int main()
{  
	__int64 n,i;

	scanf("%I64d",&n);
	getchar();
	char cha;
	__int64 tmp;

	__int64 cun=0;
	__int64 cap=0;
	for (i=1;i<=n;i++)
	{
		scanf("%c %I64d",&cha,&tmp);
		getchar(); 
		if (cha=='+')
		{
			cun++;
			vis[tmp]=1;
			if (cun>cap)
				cap=cun;
		}
		else
		{ 	
			if (vis[tmp]==1)
			{
					cun--;
					vis[tmp]=0;
			}
			else
			{ 
				cap++;   
			}

		}
	}
	printf("%I64d\n",cap);
 
	
	return 0;
	
}