#include <iostream>
#include <cstdio>
#include <cstring>
#include <string>
#include <algorithm>
using namespace std;
const int N = 5010;
int n,f[N];
struct made{
    int l,w;
}a[N];
int cmp(made x,made y){
    if(x.l == y.l)return x.w >= y.w;
    return x.l >= y.l;
}
int main(){
    cin>>n;
    for(int i = 1;i <= n;i++){
        cin>>a[i].l>>a[i].w;
        f[i] = 1;
    }
    sort(a+1,a+1+n,cmp);
    for(int i = 1;i <= n;i++)cout<<a[i].l<<' '<<a[i].w<<endl;
    cout<<endl;
    for(int i = n-1;i >= 1;i--){
        for(int j = i;j <= n;j++){
            if(a[j].w > a[i].w)f[i] = max(f[i],f[j]+1);
        }
    }
    cout<<f[1]<<endl;
    
    return 0;
}

求大佬