let n = readLine()!.split(separator: " ").map{Int($0)!}
var a = readLine()!.split(separator: " ").map{Int($0)!}
a += [a[0]]
for i in 1..<n[0]{
    a[n[0]] ^= a[i]
}
print(a[(n[1]-1)%(n[0]+1)])