#include<stdio.h>
int main() 
{
    long s,v,t,h,m;
    scanf("%ld %ld",&s,&v);
    t=s/v;
    if(s%v!=0)
    {
        t=t+1;
    }
    t=t+10;
    if(t<=8*60)
    {
        h=(8*60-t)/60;
        m=(8*60-t)%60;
    }
    else
    {
        h=(24*60+8*60-t)/60;
        m=(24*60+8*60-t)%60;
    }
    if(h<10&&m<10)
    {
        printf("0%ld:0%ld",h,m);
    }
    else if(h<10&&m>10)
    {
        printf("0%ld:%ld",h,m);
    }
    else if(h>10&&m<10)
    {
        printf("%ld:0%ld",h,m);
    }
    else if(h>10&&m>10)
    {
        printf("%ld:%ld",h,m);
    }
    return 0;
}