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

int main(){

	int h1,m1;
	cin>>h1;
	cin.ignore();
	cin>>m1;
	
	int h2,m2;
	if(m1<55){
		m2=m1+5;
		h2=h1;
	}
	else{
		m2=m1-55;
		h2=(h1+1)%24;
	}
	
	if(h2<10) cout<<0;
	cout<<h2<<":";
	if(m2<10) cout<<0;
	cout<<m2<<endl;
	
	return 0;
}