#include <stdio.h>

int main() {
	int s, v;
	scanf("%d %d", &s, &v);
	int time = (s / v) + 10;
	int H = 7 - time / 60;
	int M = 59 - time % 60;
	if(time%60==0)
	{
		M=0;
		H=H+1;
	}
	if (H >= 0) {
		printf("%02d:%02d", H, M);
	} else {
		printf("%02d:%02d", H + 24, M);
	}
	return 0;
}