include<stdio.h>

int main(){ int a,b,d; scanf("%d %d",&a,&b); if(a%b==0) d=a/b; else d=a/b+1; int f=31,e=50,p; if(d<=50) printf("%02d:%02d",f%24,e-d); if(50<d&&d<60) printf("%02d:%02d",(f-1)%24,e+60-d); if(d>=60) {if(e-d%60<0) printf("%02d:%02d",(f-d/60+1)%24,e-d%60+60); else printf("%02d:%02d",(f-d/60)%24,e-d%60);} return 0;}```c

include<stdio.h>

int main(){ int a,b,d; scanf("%d %d",&a,&b); if(a%b==0) d=a/b; else d=a/b+1; int f=31,e=50,p; if(d<=50) printf("%02d:%02d",f%24,e-d); if(50<d&&d<60) printf("%02d:%02d",(f-1)%24,e+60-d); if(d>=60) {if(e-d%60<0) printf("%02d:%02d",(f-d/60+1)%24,e-d%60+60); else printf("%02d:%02d",(f-d/60)%24,e-d%60);} return 0;}