#include <iostream>
#include<unordered_set>
#include <iomanip>
//#include <cstdio>
#include<vector>
#include <cmath>
#define ll long long
#define vi vector<int>
using namespace std;

int n;
int main()
{
    ios::sync_with_stdio(false);
    //cout << setprecision(10);
    while(cin>>n)
    {
        for(int i=0; i<n; i++) {
        int x, y;
            cin>>x>>y;
        }
        cout<<(n+1)/2<<endl;
    }






    return 0;
}