#include <bits/stdc++.h>
using namespace std;

int main()
{
	string T;
	cin >> T;

	int h, m;
	sscanf( T.c_str(), "%d:%d", &h, &m );
	char ans[16];
	if( m + 5 >= 60 ) {
		h++;
		if( h >= 24 ) h = 0;
		m = (m + 5) % 60;
	}
	else m += 5;
	sprintf( ans, "%02d:%02d", h, m );

	cout << ans << endl;
}