Lucky Segments

4000ms

262144K

Description:

Petya loves lucky numbers. Everybody knows that lucky numbers are positive integers whose decimal representation contains only the lucky digits 4 and 7. For example, numbers 47, 744, 4 are lucky and 5, 17, 467 are not.

Petya has n number segments [l₁; r₁], [l₂; r₂], ..., [l_n; r_n]. During one move Petya can take any segment (let it be segment number i) and replace it with segment [l_i + 1; r_i + 1] or [l_i - 1; r_i - 1]. In other words, during one move Petya can shift any segment to the left or to the right by a unit distance. Petya calls a number full if it belongs to each segment. That is, number x is full if for any i (1 ≤ i ≤ n) the condition l_i ≤ x ≤ r_i is fulfilled.

Petya makes no more than k moves. After that he counts the quantity of full lucky numbers. Find the maximal quantity that he can get.

Input:

The first line contains two integers n and k (1 ≤ n ≤ 10⁵, 1 ≤ k ≤ 10¹⁸) — the number of segments and the maximum number of moves. Next n lines contain pairs of integers l_i and r_i (1 ≤ l_i ≤ r_i ≤ 10¹⁸).

Please do not use the %lld specificator to read or write 64-bit integers in С++. It is preferred to use the %I64d specificator.

Output:

Print on the single line the single number — the answer to the problem.

Sample Input:

Sample Output:

Sample Input:

2 7
40 45
47 74

Sample Output:

Note:

In the first sample Petya shifts the second segment by two units to the left (it turns into [4; 7]), after that number 4 becomes full.

In the second sample Petya shifts the first segment by two units to the right (it turns into [42; 47]), and shifts the second segment by three units to the left (it turns into [44; 71]), after that numbers 44 and 47 become full.

Informação

Provedor Codeforces

Código CF121D