Odd Man Out

You are throwing a party for an odd number of guests. You sent invitations to couples only, and you wrote a different invitation code $C$ on each couple's invitation.

Because the guest count is odd, exactly one guest came without a partner. Given the invitation code that every guest reports, find the code of the guest who came alone.

The first line contains the number of test cases $N$. $N$ test cases follow, and each test case takes two lines.

• The first line contains the number of guests $G$.
• The second line contains the invitation codes $C$ of the $G$ guests, separated by spaces.

Limits

• $1 \le N \le 50$
• $0 < C \le 2147483647$
• $3 \le G < 1000$
• $G$ is odd. Each couple has a different code, so every code except the lone guest's appears exactly twice.

For each test case, print one line containing Case #x: followed by the invitation code $C$ of the guest who came alone. Here $x$ is the test case number, starting from 1.