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], ..., [ln;rn]. During one move Petya can take any segment (let it be segment number i) and replace it with segment [li+1;ri+1] or [li-1;ri-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 \le i \le n) the condition li \le x \le ri 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.

The first line contains two integers n and k (1 \le n \le 105, 1 \le k \le 1018) - the number of segments and the maximum number of moves. Next n lines contain pairs of integers li and ri (1 \le li \le ri \le 1018).

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

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

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.