#include <iostream>
#include <string>
#include <stdio.h>
using namespace std;

int main(){
	int x;
	string unko;

	cin >> unko;

	for(int i = 0;i < 5;++i){
		if( i != 2)
			unko[i]-=48;
	}

	unko[4] += 5;
	if(unko[4] > 9){
		unko[4] -=10;
		unko[3] += 1;
	}

	if(unko[3] >= 6){
		unko[3] -= 6;
		unko[1] += 1; 
	}

	if(unko[1] > 10){
		unko[1] -= 10;
		unko[0] += 1;
	}

	if(unko[0] * 10 + unko[1] >= 24){
		unko[0] -= 2;
		unko[1] -= 4;
	}

	for(int i = 0; i < 5;++i){
		if(i!= 2)
			unko[i]+=48;
		cout << unko[i];
	}

	cout <<  endl;



}