include <stdio.h>

include <math.h>

int main() { double s,v;int t,h,m; scanf("%lf%lf",&s,&v); t=ceil(s/v); h=(1440-t-10)/60; m=(1440-t-10)%60; if(h<=16&&m>=10) printf("%d:%d",8+h,m); if(h>16&&m<10) printf("0%d:0%d",h-16,m); if(h<=16&&m<10) printf("%d:0%d",8+h,m); if(h>16&&m>=10) printf("0%d:%d",h-16,m); return 0; }