using static System.Console;
public class Program {
public static void Main() {
var calculoChave = 0;
foreach (var c in new int[] {1, 2, 3, 4, 5, 6, 7, 8, 9}) calculoChave ^= c;
WriteLine(calculoChave);
}
}
//https://pt.stackoverflow.com/q/48414/101
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