text: #include<cstdio>
  main()
  {
      int x,s[3],t[3];
      while(scanf("%d:%d:%d %d:%d:%d",s,s+1,s+2,t,t+1,t+2)>0)
      {
          x=(t[0]-s[0])*3600+(t[1]-s[1])*60+t[2]-s[2];
          if(x<0)x+=86400;
          printf("%02d:%02d:%02d\n",x/3600,x/60%60,x%60);
      }
  }
  