#include <bits/stdc++.h>
using namespace std;
 
int main() {
	int ans=0;
	int b1x,b1y,b2x,b2y,tx,ty,b1x2,b1y2,b2x2,b2y2,tx2,ty2;
	cin>>b1x>>b1y>>b1x2>>b1y2>>b2x>>b2y>>b2x2>>b2y2>>tx>>ty>>tx2>>ty2;
	for(int i = -1000; i<=1000; i++){
		for(int j=-1000;j<=1000; j++){
			if((j>=b1x&&j<=b1x2-1&&i>=b1y&&i<=b1y2-1) || (j>=b2x&&j<=b2x2-1&&i>=b2y&&i<=b2y2-1)){
				if(!(j>=tx&&j<=tx2-1&&i>=ty&&i<=ty2-1)){
				ans++;	
				}
			}
		}
	}
	cout<<ans;
	return 0;
}

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MSAyIDMgNQo2IDAgMTAgNAoyIDEgOCAz

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