Euler is a well-known matematician, and, among many other things, he discovered that the formula n2 + n + 41 produces a prime for 0 ≤ n < 40. For n = 40, the formula produces 1681, which is 41 ∗ 41. Even though this formula doesn’t always produce a prime, it still produces a lot of primes. It’s known that for n ≤ 10000000, there are 47,5% of primes produced by the formula! So, you’ll write a program that will output how many primes does the formula output for a certain interval.
Each line of input will be given two positive integer a and b such that 0 ≤ a ≤ b ≤ 10000. You must read until the end of the file.
For each pair a, b read, you must output the percentage of prime numbers produced by the formula in this interval (a ≤ n ≤ b) rounded to two decimal digits.
範例輸入 1
0 39 0 40 39 40
範例輸出 1
100.00 97.56 50.00
Pro 專屬功能: 查看這題在歷屆 CPE 出現過幾次 — 升級以解鎖.