#include <iostream>
#include <stack>
#include <queue>
using namespace std;

stack<int> s;
queue<int> q;
int main() {
    int n;
    cin>>n;
    for (int i = 0; i < n; ++i) {
        int flag=0,x=0;
        scanf("%d %d",&x,&flag);
        if (flag == 1){
            s.push(x);
        }else if (s.empty() && flag==0){
            q.push(x);
        }else{
                while(!s.empty()){
                    int a = s.top();
                    if (x>a) s.pop();
                    else{
                        break;
                    }
                }
                if (s.empty()) q.push(x);
        }
    }
    cout<<s.size()+q.size()<<endl;

    return 0;
}

#include <bits/stdc++.h>
using namespace std;
typedef pair <int,int> PII;
vector <PII> vec;
stack <PII> stk;
int main() {
    int N;
    cin >> N;
    for (int i = 0; i < N; i++) {
        int a, b;
        cin >> a >> b;
        vec.push_back(make_pair(a, b));
    }

    for (int i = 0; i < N; i++) {
        if (stk.empty()) {
            stk.push(vec[i]);
        } else {
            int d = vec[i].second;
            int topd = stk.top().second;
            int s = vec[i].first;
            int stks = stk.top().first;  
            if (d < topd && s > stks) {
                // judge empty write fisrt !!!
                // 1 0 1 1 0
                while (stk.size() != 0 && stk.top().first < s && stk.top().second != 0) {
                   // cout << stk.top().first << endl;
                    stk.pop();
                }
                if (stk.size() == 0) { 
                    stk.push(vec[i]);
                } else if (stk.top().second == 0) {
                    stk.push(vec[i]);
                }
            } else if (d >= topd) {
                stk.push(vec[i]);
            } 
        }
    }
    cout << stk.size();
    return 0;
}