27分，玄学贪心

#include<bits/stdc++.h>
using namespace std;
const int N=5005;
int n;
struct node{
	int l,w,pos;
}a[N],x[N],y[N];
bool cmp1(node x,node y){
	return x.l<y.l;
}
bool cmp2(node x,node y){
	return x.w<y.w;
}
bool cmp3(int x,int y){
	return x>y;
}
int sum[N];
int main(){
/*
	freopen("strick.in","r",stdin);
	freopen("strick.in","w",stdout);
	致敬小木棒(strick)	
*/	
	cin>>n;
	
	for(int i=1;i<=n;i++){
		cin>>a[i].l>>a[i].w;
		a[i].pos=i;
		x[i]=a[i];
		y[i]=a[i];
	}
	sort(x+1,x+n+1,cmp1);
	sort(y+1,y+n+1,cmp2);
	int cnt1=0;
	for(int i=1;i<=n;i++){
		cnt1+=(x[i].l<x[i+1].l||x[i].w<x[i+1].w)?1:0;
	}
	int cnt2=0;
	for(int i=1;i<=n;i++){
		cnt2+=(y[i].l<y[i+1].l||y[i].w<y[i+1].w)?1:0;
	}
	if(ceil(min(cnt1,cnt2)/2)){
		cout<<ceil(min(cnt1,cnt2)/2);
	}else{
		cout<<1;
	}
	
		
	return 0;
}