Read problems statements in Mandarin Chinese, Russian and Vietnamese as well.
Read problems statements in Mandarin Chinese, Russian and Vietnamese as well.
Chef recently learned about ratios and proportions. He wrote some positive integers a, b, c, d on a paper. Chef wants to know whether he can shuffle these numbers so as to make some proportion? Formally, four numbers x, y, z, w are said to make a proportion if ratio of x : y is same as that of z : w.

------ Input ------

Only line of the input contains four space separated positive integers - a, b, c, d.

------ Output ------

Print "Possible" if it is possible to shuffle a, b, c, d to make proportion, otherwise "Impossible" (without quotes).

------ Constraints ------

$1 ≤ a, b, c, d ≤ 1000$

----- Sample Input 1 ------
1 2 4 2
----- Sample Output 1 ------
Possible
----- explanation 1 ------
By swapping 4 and the second 2, we get 1 2 2 4. Note that 1 2 2 4 make proportion as 1 : 2 = 2 : 4. Hence answer is "Possible"

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