#include <iostream>
using namespace std;
int Sifriranje(int n, int sifra) {
	int s = 0;
	int ost = 0;
	for (int i = 1; i <= n; i++)
	{
		ost = n % 10;
		if (ost % 3 == 0)
			sifra = ost;
		s += sifra*pow(10.0, i);
		n /= 10;
	}
	return s;
}
void main() {
	int sifra;
	int n;
	do {
		cin >> n;
	} while (n < 0);
	cout << "Unesite sifru: " << endl;
	cin >> sifra;
	cout << "Nakon sifriranja: " << Sifriranje(n, sifra) << endl;
}