#include <iostream>
#include<string>

using namespace std;


main(){
	int h,m;
	char f;
	
	cin >> h >> f >>m;
	
	h=(h+m/55)%24;
	m=(m+5)%60;
	
	cout<<h/10<<h%10<<":"<<m/10<<m%10<<endl;
	return 0;
}