Let be the smallest divisor of greater than . For example, f(12) = 2, f(13) = 13.
Let be the number of divisors of . For example, d(18) = 6, since has divisors: 1, 2, 3, 6, 9, 18.
Find the value of the following sum:
where is a given number.
Two positive integers n~(2 \le n \le 10^7) and m~(m \le 10^9).
Print the value of the sum .
For n = 5, the answer is S = 2^2 + 2^3 + 3^2 + 2^5 = 53.
Example 1