Write a function solution that, given two integers a and b, returns the maximum number of repeated square root operations that can be performed using the numbers from the interval [a..b](both ends included) as starting points. square root operations can be performed as long as the result is still an integer.
for example, given a = 10, b = 20, the function should return 2. starting with the integer 16, two square root operations can be performed: sqrt(16) = 4 and then sqrt(4) = 2.
given a = 6000 and b = 7000, the function should return 3. starting with integer 6561, three square root operations can be performed: sqrt(6561) = 81, sqrt(81) = 9 and sqrt(9) = 3.