> /*
> 1155534 Rpmes 2815 Accepted 40K 0MS GCC 0.42K 2006-04-15 23:06:51.0 
> 1155533 Rpmes 2815 Wrong Answer   C 0.42K 2006-04-15 23:06:41.0 
> */
> 
> //PKU2815.c
> #include <stdio.h>
> 
> int main()
> {
> 	int A, HH, MM, SS, Sec;
> 	double round, T;
> 	
> 	round = 3600 * 12 / 11.0;
> 
> 	while (scanf("%d %d:%d:%d", &A, &HH, &MM, &SS) != -1 && A != -1)
> 	{
> 		Sec = HH * 3600 + MM * 60 + SS;
> 		T = round * A / 360;
> 		while (T < Sec)
> 		{
> 			T += round;
> 		}
> 		Sec = (int)T;
> 		Sec %= 86400;
> 		printf("%02d:%02d:%02d\n", Sec / 3600, Sec % 3600 / 60, Sec % 60);
> 	}
> 	return 0;
> }