#include<cstdio>

int main() {
	int s, v, times;
	double time = 8.0 * 60.0, use_time, need_time;
	scanf("%d%d", &s, &v);
	use_time = s / v + 11.0;
	need_time = time - use_time;
	times = (int)need_time;
	if (times > 0)
	{
		printf("%02d:%02d", times / 60, times % 60);
	}
	else if(times < 0) {
		printf("%02d:%02d",23 + times / 60, 60+times % 60);
	}
	return 0;
}