Arthur has two natural numbers — x and y (x < y). Help him find a natural number z such that:
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z > x;
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z > y;
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z is not divisible by x;
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z is not divisible by y;
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z is divisible by y - x;
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z minimal.
Input data format
The first line contains numbers x and y (x, y ≤ 10< sup>6)
Output Format
Print the number z or '0' if it doesn't exist.
Input:
1 2
Output:
0