#include <iostream>
#include <fstream>
#include <string>
#include <vector>

int main(void) {

	//std::ifstream inf("Text.txt");	std::cin.rdbuf(inf.rdbuf());
	std::string T;
	std::cin >> T;

	if (T[4] >= '5') {
		T[4] -= 5;
		if (T[3] == '5') {
			T[3] = '0';
			if (T[1] == '9') {
				T[1] = '0';
				T[0] += 1;
			}
			else if (T[1] == '3' && T[0] == '2') {
				T[0] = T[1] = '0';
			}
			else {
				T[1] += 1;
			}
		}
		else {
			T[3] += 1;
		}
	}
	else {
		T[4] += 5;
	}

	std::cout << T << std::endl;

	return 0;
}