var a,b,c,d,e,f,g:longint;
begin
read(a);
b:=a mod 10;
c:=a div 10 mod 10;
d:=a div 100 mod 10;
e:=a div 1000 mod 10;
f:=b*1000+c*100+d*10+e;
g:=a-f;
         write(g);
         end.
/**************************************************************
	Problem: 1702
	User: admin
	Language: Pascal
	Result: Wrong Answer
****************************************************************/