#include<iostream> #include<cstdio> #include<iomanip> #include<string> using namespace std; int main() { int num; cin>>num; int a,b,c,d; a=num%10; b=num%100/10; c=num%1000/100; d=num/1000; cout<<c*1000+d*100+a*10+b; return 0; }