#define _CRT_SECURE_NO_WARNINGS
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <bitset>
#include <time.h>
#include <string>
#include <vector>
#include <math.h>
#include <cassert>
#include <iostream>
#include <algorithm>

using namespace std;

#define ft first
#define sc second
#define mp make_pair
#define all(a) a.begin(), a.end()
#define forn(i, n) for (int i = 0; i < int(n); i++)

typedef long long li;
typedef long double ld;
typedef pair <li, li> pli;
typedef pair <int, int> pii;

const int N = 1000100;

int n;

bool in[N];

int main()
{
    cin >> n;
    int mx = 0, tx = 0;
    forn(i, n)
    {
        char z; int idx;
        cin >> z >> idx;
        if(z == '-')
        {
            if(!in[idx])
                mx++;
            else
                tx--;
            in[idx] = false;
        }
        else
        {
            tx++;
            mx = max(mx, tx);
            in[idx] = true;
        }
    }
    
    cout << mx;

    return 0;
}