import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.*;
class Solution
{
public static void main(String args[]) throws Exception
{
Scanner sc = new Scanner(System.in);
StringBuffer sb = new StringBuffer();
int T = Integer.parseInt(sc.nextLine());
for (int tc = 1; tc <= T; tc++) {
System.out.print("#" + tc + " ");
SimpleDateFormat f = new SimpleDateFormat("HH:mm:ss", Locale.KOREA);
Date d1 = f.parse(sc.nextLine());
Date d2 = f.parse(sc.nextLine());
long diff = 0;
if(d1.after(d2)){
Calendar cal = Calendar.getInstance();
cal.setTime(d2);
cal.add(Calendar.HOUR, 24);
d2 = cal.getTime();
}
diff = d2.getTime() - d1.getTime();
long h = (diff / (1000 * 60 * 60));
long m = (diff % (1000 * 60 * 60) / (1000 * 60));
long s = ((diff % (1000 * 60 * 60) % (1000 * 60))) / 1000;
System.out.format("%02d:%02d:%02d", h, m ,s);
System.out.print("\n");
}
}
}