x1 = 2;
x2 = 2;
x3 = 2;
----------
x1 = 2;
x2 = 2;
x3 = 1;
----------
x1 = 1;
x2 = 2;
x3 = 2;
----------
x1 = 1;
x2 = 2;
x3 = 1;
----------
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