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문제

One lovely afternoon, Bessie's friend Heidi was helping Bessie review for her upcoming math exam.

Heidi presents two integers A (0 <= A <= 45) and B (1 <= B <= 9) to Bessie who must respond with an integer E in the range 1..62. E is the smallest integer in that range that is strictly greater than A and also has B as the first digit of 2 raised to the E-th power. If there is no answer, Bessie responds with 0.

Help Bessie correctly answer all of Heidi's questions by calculating her responses.

By way of example, consider A=1 and B=6. Bessie might generate a table like this:

         E         2^E    First digit of 2^E
         2          4            4
         3          8            8
         4         16            1
         5         32            3
         6         64            6      <-- matches B

Thus, E=6 is the proper answer.

NOTE: The value of 2^44 does not fit in a normal 32-bit integer.

입력

  • Line 1: Two space-separated integers: A and B

 

출력

  • Line 1: A single integer E calculated as above

 

예제 입력

1 6

예제 출력

6

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