#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,n; cin>>n; a=n/1000; b=n%1000/100; c=n%100/10; d=n%10; cout<<b*1000+a*100+d*10+c<<"\n"; return 0; }