#include <bits/stdc++.h>
using namespace std;
int main()
{
	int h,m;
	char a;
	cin >> h >> a >> m;
	if(h == 23 && m == 59) 
	{
		cout << "00:00";
		return 0;
	}
	m += 1;
	for(int i = 0;;i++){
		if((h % 10 * 10 + h / 10) == m){
			cout << h << ":" << m;
			return 0;
		}
		if(m == 59){ 
			m = 0,h++;
			if(h == 24) h = 0;
		}
		else m++;
	}
}