#include<stdio.h>
int main(){
    int s,v;
    scanf("%d %d",&s,&v);
    int t=s/v;
    if(s%v=0){
        int shi=(t+10)/60;
        int fen=(t+10)%60;
        if(t+10<=480){
            if(fen<=50)
              printf("0%d:%d",8-shi,60-fen);
              else printf("0%d:0%d",8-shi,60-fen);}
            else if(fen<=50){
                if(32-shi>=10)
                printf("%d:%d",32-shi,60-fen)
                else printf("0%d:%d",32-shi,60-fen)
                }
        else if(fen>50){
            if(32-shi>=10)
            printf("%d:0%d",32-shi,60-fen)
            else printf("0%d:0%d",32-shi,60-fen)}
    }
    else {
        int shi=(t+11)/60;
        int fen=(t+11)%60;
        if(t+11<=480){
            if(fen<=50)
              printf("0%d:%d",8-shi,60-fen);
            else printf("0%d:0%d",8-shi,60-fen);}
        else if(fen<=50){
            if(32-shi>=10)
                printf("%d:%d",32-shi,60-fen)
            else printf("0%d:%d",32-shi,60-fen)}
        else if(fen>50){
            if(32-shi>=10)
            printf("%d:0%d",32-shi,60-fen)
            else printf("0%d:0%d",32-shi,60-fen)}
    }
    return 0;


}