Background

Description

Given a non-negative int n, return the count of the occurrences of 7 as a digit, so for example 717 yields 2. (no loops). Note that mod (%) by 10 yields the rightmost digit (126 % 10 is 6), while divide (/) by 10 removes the rightmost digit (126 / 10 is 12).

Format

Input

Output

Samples

717

2

7

1

123

0

Limitation

1s, 1024KiB for each test case.