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 [l 1; r 1], [l 2; r 2], ..., [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.

输入描述:

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 li and ri(1 ≤ li ≤ ri ≤ 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.

输出描述:

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

备注:

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.