find minimum number of integers, (where each such integer>=2) that divide all array elements. For example, if the array is [2,4,6,8,10] then the answer is 1 (because 2 divides all array elements). Another example, if the array is [2,3,4,9] then the answer is 2 (because we need at least 2 different numbers, 2 and 3, that satisfy the conditions).