#include<bits/stdc++.h>
using namespace std;
int n;
int ans;
struct abc
{
	int x;
	int y;
}sb[10006];
bool px(abc a,abc b)
{
	return a.y<b.y;
}
bool px2(abc c,abc d)
{
	return c.x>d.x;
}
int main()
{
	scanf("%d",&n);
	for(int i=1;i<=n;i++)
		scanf("%d%d",&sb[i].x,&sb[i].y);
	sort(sb+1,sb+n+1,px);
	int mid=(n+1)/2;
	for(int i=1;i<=n;i++)
		ans+=abs(sb[mid].y-sb[i].y);
	sort(sb+1,sb+n+1,px2);
	for(int i=1;i<=n;i++)
	{
		while(sb[i].x==sb[i+1].x)
		{
			sb[i+1].x--;
			ans++;
		}
	}
	printf("%d",ans);
    return 0;
}