#include<iostream> // cin\cout\endl #include<cstdio> //scanf()\printf() #include<cstring> // strcpy()\strcat()\strcmp()\strlen()\memset() #include<cmath> //sqrt()\pow()\abs()\ceil()\floor()\max()\min() using namespace std; int main(){ int a,b,c,d,h; cin>>h; a=h%10; b=h%100/10; c=h/100%10; d=h/1000; h=c*1000+d*100+a*10+b; cout<<h; return 0; }