var a,b,c,d,e,f:longint;
begin;
read(a);
b:=a mod 10;
c:=a div 10 mod 10;
d:=a div 100 mod 10;
e:=a div 1000;
f:=d*1000+e*100+b*10+c;
write(f);
end.
/**************************************************************
	Problem: 1619
	User: admin
	Language: Pascal
	Result: Wrong Answer
****************************************************************/