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 a number consisting of n digits without leading zeroes. He represented it as an array of digits without leading zeroes. Let's call it d . The numeration starts with 1 , starting from the most significant digit. Petya wants to perform the following operation k times: find the minimum x (1 ≤ x < n ) such that d x = 4 and d x + 1 = 7 , if x is odd, then to assign d x = d x + 1 = 4 , otherwise to assign d x = d x + 1 = 7 . Note that if no x was found, then the operation counts as completed and the array doesn't change at all. You are given the initial number as an array of digits and the number k . Help Petya find the result of completing k operations. The first line contains two integers n and k (1 ≤ n ≤ 10 5 , 0 ≤ k ≤ 10 9 ) — the number of digits in the number and the number of completed operations. The second line contains n digits without spaces representing the array of digits d , starting with d 1 . It is guaranteed that the first digit of the number does not equal zero. In the single line print the result without spaces — the number after the k operations are fulfilled. In the first sample the number changes in the following sequence: 4727447 → 4427447 → 4427477 → 4427447 → 4427477 . In the second sample: 4478 → 4778 → 4478 .