A natural number is special if it consists of only digits $4$ and $7$. Find the number of pairs of сoprime special numbers $(x,\ y)$ such that $1 ⩽ x ⩽ y ⩽ N$. 

Input format

The first line contains an integer $N$ ($1 ⩽ N ⩽ 10^9$).

Output format

Print a single number denoting the answer to the problem.