#include<cstdio>

#include<cstring>

#include<cmath>

#include<algorithm>

using namespace std;

struct X

{

    int x,y;

}s[],tmp[];

int n;

int main()

{

    scanf("%d",&n);

    for(int i=;i<=n;i++)

        scanf("%d%d",&s[i].x,&s[i].y);

    int flag=-;

    for(int i=;i<=n;i++)

    {

        for(int j=;j<=n;j++)

        {

            if(s[i].x!=s[j].x&&s[i].y!=s[j].y)

            {

                flag=;

                tmp[]=s[i];

                tmp[]=s[j];

                tmp[].x=s[i].x; tmp[].y=s[j].y;

                tmp[].x=s[j].x; tmp[].y=s[i].y;

                break;

            }

        }

        if(flag==) break;

    }

    if(flag==-) printf("-1\n");

    else

    {

        flag=;

        for(int i=;i<=n;i++)

        {

            bool f=;

            for(int j=;j<=;j++)

            {

                if(s[i].x==tmp[j].x&&s[i].y==tmp[j].y) f=;

            }

            if(f==) flag=-;

        }

        if(flag==-) printf("-1\n");

        else{

            printf("%d\n",abs(tmp[].x-tmp[].x)*abs(tmp[].y-tmp[].y));

        }

    }

    return ;

}