1011 B | 1011 chars
"""
[12596: Odd Man Out (Large)](https://www.acmicpc.net/problem/12596)
Tier: Silver 5
Category: arithmetic, data_structures, hash_set, math, sorting, set
"""
import sys
from math import sqrt, pi, sin, factorial, ceil, floor
from datetime import datetime, timedelta
SYS_INPUT = True
RECURSION_LIMIT = 10 ** 7
SET_RECURSION = False
BLANK = " "
if SET_RECURSION:
sys.setrecursionlimit(RECURSION_LIMIT)
inp = lambda : sys.stdin.readline().rstrip() if SYS_INPUT else input()
mii = lambda : [*map(int,inp().split())]
mfi = lambda : [*map(float,inp().split())]
ii = lambda : int(inp())
fi = lambda : float(inp())
isplit = lambda : inp().split()
p = print
def gcd(a, b): return gcd(b, a % b) if b > 0 else a
def lcm(a, b): return a * b // gcd(a, b)
def solve():
n = ii()
l = sorted(mii())
for i in range(0, n, 2):
if i + 1 < n and l[i] != l[i+1]:
return l[i]
return l[-1]
if __name__ == "__main__":
tc = ii()
for t in range(1, tc+1):
ret = solve()
p(f"Case #{t}: {ret}")