Wonowon Numbers

A small village in northern Canada is named Wonowon, because it sits at Mile 101 of the Alaska Highway. A travelling mathematician passed through the village and named a family of numbers after it. A wonowon number is a positive integer whose decimal representation starts with 1, ends with 1, and alternates between 1 and 0. The four smallest wonowon numbers are 101, 10101, 1010101 and 101010101, so a wonowon number always has an odd number of digits, at least three.

No wonowon number is divisible by 2 or by 5. Every other prime is conjectured to divide some wonowon number. For example, 3 divides 10101 ($3 \times 3367$), 7 divides 10101 ($7 \times 1443$), and 11 divides 101010101010101010101 ($11 \times 9182736455463728191$).

Assume the conjecture holds, and let $W(p)$ be the number of digits of the smallest wonowon number divisible by the prime $p$. Then $W(3) = 5$, $W(7) = 5$, $W(11) = 21$, $W(13) = 5$, $W(17) = 15$ and $W(19) = 17$.

Experiments show that $W(p) = p - 2$ holds for many primes, among them 7, 17 and 19. Given an integer $n$, count the primes $p$ with $p \le n$, $p \ne 2$, $p \ne 5$ and $W(p) = p - 2$.

The first and only line contains one integer $n$. ($3 \le n \le 10000$)

Print, on one line, the number of primes $p$ with $p \le n$, $p \ne 2$, $p \ne 5$ and $W(p) = p - 2$.