C++ :

#include<iostream>
#include<algorithm>
#include<cstdlib>
using namespace std;
int main()
{
    int n;
    cin>>n;
    int x[n+1],y[n+1],sum=0;
    for(int i=1;i<=n;i++)
        cin>>x[i]>>y[i];
    sort(y+1,y+n+1);
    if(n%2==1)
    {
        int t=y[n/2+1];
        for(int i=1;i<=n;i++)
        {
            if(y[i]>t) sum+=y[i]-t;
            if(y[i]<=t) sum+=t-y[i];
        }
    }
    if(n%2==0)
    {
        int t=(y[n/2]+y[n/2+1])/2;
        for(int i=1;i<=n;i++)
        {
            if(y[i]>t) sum+=y[i]-t;
            if(y[i]<=t) sum+=t-y[i];
        }
    }
    cout<<sum;
    return 0;
}