Petya loves lucky numbers. We all know that lucky numbers are the positive integers whose decimal representations contain only the lucky digits 4 and 7 . For example, numbers 47 , 744 , 4 are lucky and 5 , 17 , 467 are not. Petya and his friend Vasya play an interesting game. Petya randomly chooses an integer p from the interval p l , p r and Vasya chooses an integer v from the interval v l , v r (also randomly). Both players choose their integers equiprobably. Find the probability that the interval min ( v , p ), max ( v , p ) contains exactly k lucky numbers. The single line contains five integers p l , p r , v l , v r and k ( 1 ≤ p l ≤ p r ≤ 10 9 , 1 ≤ v l ≤ v r ≤ 10 9 , 1 ≤ k ≤ 1000 ). On the single line print the result with an absolute error of no more than 10 - 9 . Consider that a , b denotes an interval of integers; this interval includes the boundaries. That is, In first case there are 32 suitable pairs: (1, 7), (1, 8), (1, 9), (1, 10), (2, 7), (2, 8), (2, 9), (2, 10), (3, 7), (3, 8), (3, 9), (3, 10), (4, 7), (4, 8), (4, 9), (4, 10), (7, 1), (7, 2), (7, 3), (7, 4), (8, 1), (8, 2), (8, 3), (8, 4), (9, 1), (9, 2), (9, 3), (9, 4), (10, 1), (10, 2), (10, 3), (10, 4) . Total number of possible pairs is 10·10 = 100 , so answer is 32 / 100 . In second case Petya always get number less than Vasya and the only lucky 7 is between this numbers, so there will be always 1 lucky number.