Odd Man Out

You are hosting a party for $G$ guests. You sent invitations to couples only, and each couple got its own invitation number $C$, the same number for both partners. A couple adds two guests carrying the same number, so the guest count should be even. It is not: the number of guests $G$ who showed up is odd, so exactly one guest came alone.

You ask every guest for an invitation number and write the answers down. Find the invitation number of the guest who came alone.

The first line contains the number of test cases $N$.

Each test case is given on two lines.

• The first line contains the number of guests $G$.
• The second line contains $G$ space separated integers, the invitation number $C$ of each guest.

Limits

• $1 \le N \le 50$
• $3 \le G < 100$, and $G$ is odd.
• $0 < C \le 2147483647$
• In each test case exactly one number appears once and every other number appears exactly twice.

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