#include <bits/stdc++.h>

#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>

using namespace __gnu_pbds;
using namespace std;

//#pragma comment(linker, "/stack:200000000")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")

#pragma GCC optimize("unroll-loops")
#pragma GCC optimize("Ofast")
#pragma GCC optimize("-O")
#pragma GCC optimize("-s")
#pragma GCC optimize("-Os")
#pragma GCC optimize("-O1")
#pragma GCC optimize("-O2")
#pragma GCC optimize("-O3")

#define ll long long
#define ld long double
#define int ll
#define F first
#define S second
#define pb push_back
#define pf push_front
#define endl '\n'
#define TIME 1.0*clock()/CLOCKS_PER_SEC
#define pii pair<int, int>
#define Tip pii

typedef tree< Tip, null_type, less<Tip>, rb_tree_tag, tree_order_statistics_node_update> ord_set;

#ifdef SashOK
#else
#define cerr if(0)cerr
#endif

const int inf = 1e9;

main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
#ifdef SashOK
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#else
//    freopen("input.txt", "r", stdin);
//    freopen("output.txt", "w", stdout);
//    freopen("INPUT.TXT", "r", stdin);
//    freopen("OUTPUT.TXT", "w", stdout);
//    freopen("forest.in", "r", stdin);
//    freopen("forest.out", "w", stdout);
#endif
    int n;
    cin >> n;
    vector<pii> m;
    vector<pii> p;
    int mm = 0, pp = 0;
    int ODIN = 0;
    int ans = 0;
    for(int i = 0; i < n; i++)
    {
        int x, t;
        cin >> x >> t;
        if(x == 0 && t != 0)
        {
            ODIN++;
            continue;
        }
        if(x > 0)
        {
            p.pb({x, t});
        }
        else
        {
            m.pb({-x, t});
        }
//        a.pb({x, t});
    }
    sort(m.begin(), m.end());
    sort(p.begin(), p.end());
    int id = 1;
//    ord_set mem;
//    mem.insert({1, 1});
//    mem.insert({2, 2});
//    mem.insert({3, 3});
//    mem.insert({4, 4});
//    cout << mem.order_of_key({2, -1});
//    return 0;
    /// 1)<- 2)->

//    for(auto to:m)cout << to.F << ' ' << to.S << endl;
//    cout << endl;
//    for(auto to:p)cout << to.F << ' ' << to.S << endl;

    ord_set st1;
    for(int i = 0; i < m.size(); i++)
    {
        if(m[i].S > m[i].F)
        {
            st1.insert({m[i].S - m[i].F, id});
            id++;
        }
    }
//    for(auto to:st1)
//    {
//        cout << to.F << ' ';
//    }
    int k1 = 0;
    for(int i = 0; i < p.size(); i++)
    {
        if(p[i].F < p[i].S)
        {
            k1++;
            ans = max(ans, k1 + st1.size() - st1.order_of_key({p[i].F * 2 + 1, -1}));
        }
    }
    /// 1)-> 2)<-
    ord_set st2;
    for(int i = 0; i < p.size(); i++)
    {
        if(p[i].S > p[i].F)
        {
            st2.insert({p[i].S - p[i].F, id});
            id++;
        }
    }
    int k2 = 0;
    for(int i = 0; i < m.size(); i++)
    {
        if(m[i].F < m[i].S)
        {
            k2++;
            ans = max(ans, k2 + st2.size() - st2.order_of_key({m[i].F * 2 + 1, 0}));
        }
    }
    int ansver = ans + ODIN;
    if(ansver > 0 && ansver % 2 == 0)ansver--;
    cout << ansver;
}