#include <bits/stdc++.h> using namespace std; int main() { int a, b, c, d; int x; cin >> x; //1234 a = x / 1000;//1 b = x / 100 % 10;//2 c = x % 100 / 10; //3 d = x % 10;//4 //2143 cout<<b*1000+a*100+d*10+c; return 0; }