#include<iostream>
using namespace std;
struct qwe
{
int x, y, x1, y1;
};
int main()
{
int n[202][202] = { 0 }, i, j, q, w=0;
qwe a, b, c;
cin >> a.x >> a.y >> a.x1 >> a.y1 >> b.x >> b.y >> b.x1 >> b.y1 >> c.x >> c.y >> c.x1 >> c.y1;
q = min(a.x, a.x1);
a.x1 = max(a.x, a.x1);
a.x = q;
q = min(a.y, a.y1);
a.y1 = max(a.y, a.y1);
a.y = q;
q = min(b.x, b.x1);
b.x1 = max(b.x, b.x1);
b.x = q;
q = min(b.y, b.y1);
b.y1 = max(b.y, b.y1);
b.y = q;
q = min(c.x, c.x1);
c.x1 = max(c.x, c.x1);
c.x = q;
q = min(c.y, c.y1);
c.y1 = max(c.y, c.y1);
c.y = q;
for (i = a.x; i <= a.x1; i++)
for (j = a.y; j <= a.y1; j++)
n[i+101][j+101] = 1;
for (i = b.x; i <= b.x1; i++)
for (j = b.y; j <= b.y1; j++)
n[i+101][j+101] = 1;
for (i = b.x; i <= b.x1; i++)
for (j = b.y; j <= b.y1; j++)
n[i+101][j+101] = 1;
for (i = 1; i <= 201; i++)
for (j = 1; j <= 201; j++)
w += a[i][j];
cout << w;
}
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