#include <stdio.h>
#include <stdlib.h>

int obrnip(int x, int red);
int obrni(int x);

int main(){
	printf("%d\n",obrni(12345));
	return 0;
}



int obrnip(int x, int red){
	if(x==0)
		return 0;
	else
		return obrnip(x/10,red/10)+(x%10)*red; 
}

int obrni(int x){
	int k=1,y;
	y=x;
	while(x){
		k*=10;
		x/=10;
	}
	return obrnip(y,k/10);
}