var a:array[-1000000000..1000000000,-1000000000..1000000000] of 0..1;
    x0,x1,y0,y1,i,j,con:longint;
    f,g:text;
    begin
assign(f,'reuniune.in'); reset(f);
assign(g,'reuniune.out'); rewrite(g);
read(f,x0,y0,x1,y1);
con:=0;
for i:=y0 to y1 do
for j:=x0 to x1 do begin
        a[i,j]:=1;
        inc(con);
         end;
for i:=y0 to y1 do
for j:=x0 to x1 do begin
        if a[i,j]=1 then inc(con);
        a[i,j]:=1;
         end;
read(f,x0,y0,x1,y1);
for i:=y0 to y1 do
for j:=x0 to x1 do begin
        if a[i,j]=1 then inc(con);
        a[i,j]:=1;
         end;
read(f,x0,y0,x1,y1);
for i:=y0 to y1 do
for j:=x0 to x1 do begin
        if a[i,j]=1 then inc(con);
        a[i,j]:=1;
         end;


end.