A8796. Roma and Lucky Numbers
编程题
普及/提高-
知识点
题目描述
Roma (a popular Russian name that means 'Roman') loves the Little Lvov Elephant's lucky numbers.
Let us remind you that lucky numbers are positive integers whose decimal representation only contains lucky digits $4$ and $7$ . For example, numbers $47$ , $744$ , $4$ are lucky and $5$ , $17$ , $467$ are not.
Roma's got $n$ positive integers. He wonders, how many of those integers have not more than $k$ lucky digits? Help him, write the program that solves the problem.
Let us remind you that lucky numbers are positive integers whose decimal representation only contains lucky digits $4$ and $7$ . For example, numbers $47$ , $744$ , $4$ are lucky and $5$ , $17$ , $467$ are not.
Roma's got $n$ positive integers. He wonders, how many of those integers have not more than $k$ lucky digits? Help him, write the program that solves the problem.
输入格式
The first line contains two integers $n$ , $k$ $(1<=n,k<=100)$ . The second line contains $n$ integers $a_{i}$ $(1<=a_{i}<=10^{9})$ — the numbers that Roma has.
The numbers in the lines are separated by single spaces.
The numbers in the lines are separated by single spaces.
输出格式
In a single line print a single integer — the answer to the problem.
输入输出样例
输入 #1
3 4 1 2 4
输出 #1
3
输入 #2
3 2 447 44 77
输出 #2
2
说明/提示
In the first sample all numbers contain at most four lucky digits, so the answer is $3$ .
In the second sample number $447$ doesn't fit in, as it contains more than two lucky digits. All other numbers are fine, so the answer is $2$ .
In the second sample number $447$ doesn't fit in, as it contains more than two lucky digits. All other numbers are fine, so the answer is $2$ .