#include<stdio.h>
int main(){
    int s,v,a;
    scanf_s("%d %d",&s,&v);
    int n=1920;
    int q, w;
    if (s % v == 0){
        a = s/v + 10;
    }
    else a = s/v+11;
    n=n-a;
    if(n>=24*60){
        n = n - 24 * 60;
        q = n / 60;
        w = n % 60;
    }
    else{
        q = n / 60;
        w = n % 60;
    }
    if (q<10){
        printf("0%d:%d",q,w);
    }else printf("%d:%d",q,w);
    return 0;
}