package main

import (
	"bufio"
	"fmt"
	"os"
)

func main() {
	in := bufio.NewReader(os.Stdin)
	var t int
	if _, err := fmt.Fscan(in, &t); err != nil {
		return
	}
	for i := 0; i < t; i++ {
		var n int
		fmt.Fscan(in, &n)
		var or, and int
		for j := 0; j < n; j++ {
			var x int
			fmt.Fscan(in, &x)
			if j == 0 {
				or = x
				and = x
			} else {
				or |= x
				and &= x
			}
		}
		fmt.Println(or - and)
	}
}