count = int(input())
points = []
for i in range(count):
point = tuple([int(n) for n in input().split()])
points.append(point)
answer = 0
for (x, y) in points:
left = False
right = False
up = False
low = False
for (x1, y1) in points:
if x1 > x and y1 == y:
right = True
if x1 < x and y1 == y:
left = True
if x1 == x and y1 > y:
up = True
if x1 == x and y1 < y:
low = True
if left and right and up and low:
answer += 1
print(answer)#include <iostream>
#include <bits/stdc++.h>
#include <map>
#include <vector>
#include <string>
using namespace std;
#define ll long long
int main(){
ll n;
cin>>n;
ll t=0;
ll arx[n];
ll ary[n];
for(ll i=0;i<n;i++){
cin>>arx[i]>>ary[i];
}
for( ll i=0;i<n;i++){
bool a=false, b=false,c=false,d=false;
for(ll j=0 ; j<n;j++){
if(arx[j]>arx[i] && ary[j]==ary[i]) a=true;
if(arx[j]==arx[i] && ary[j]>ary[i]) b=true;
if(arx[j]<arx[i] && ary[j]==ary[i]) c=true;
if(arx[j]==arx[i] && ary[j]<ary[i]) d=true;
}
if(a&&b&&c&&d){
t++;
}
}
cout<<t<<endl;
return 0;
} 1302. Deepest Leaves Sum | 1209. Remove All Adjacent Duplicates in String II |
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866. Prime Palindrome | 1516A - Tit for Tat |
622. Design Circular Queue | 814. Binary Tree Pruning |
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518. Coin Change 2 | 516. Longest Palindromic Subsequence |
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