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. The first line contains two integers n and k ( 1 ≤ n ≤ 10 5 , 1 ≤ k ≤ 10 18 ) — 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 ≤ 10 18 ) . Please do not use the %lld specificator to read or write 64-bit integers in С++. 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.