#include<bits/stdc++.h> using namespace std; int main(){ int a; cin>>a; if(a<1000 || a > 9999) return 1; int g,s,b,q; g = a%10; s = a/10%10; b = a/100%10; q = a/1000; printf("%04d\n",g*1000+q*100+b*10+s); return 0; }