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Problem Description

Jixiang has a unique theory about lucky numbers: he believes that if the sum of the digits of a positive integer is divisible by 7, then that number is his lucky number.

Now, Jixiang wants to know how many such lucky numbers exist within a certain range. Given two integers l and r, representing a closed interval [l, r], please help Jixiang calculate how many numbers in this interval (including both l and r) satisfy the condition that the sum of their digits is a multiple of 7.

Note: The interval includes both endpoint values l and r.

Input Format

Two integers l and r, separated by a space (1 ≤ l ≤ r ≤ 10^6)

Output Format

An integer representing the count of lucky numbers in the interval [l, r]

Sample Input #1

1 20

Sample Output #1

2

Sample Input #2

7 7

Sample Output #2

1

Explanation/Hint

Explanation for Sample 1: Between 1 and 20, the number 7 (7÷7=1) and the number 16 (1+6=7÷7=1) are lucky numbers.

This problem uses Subtask bundling test