Nearly Lucky Number

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Nearly Lucky Number

Determine whether a number is nearly lucky: it contains only the digits 4 and 7, and the count of its lucky digits is itself lucky.

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Problem Statement

A positive integer is called lucky if every digit in its decimal representation is either 4 or 7.

A number is called nearly lucky if the number of lucky digits it contains is itself a lucky number.

Given an integer, decide whether it is nearly lucky.

Clarification

Count only digits 4 and 7 in the number.
Then check whether that count is a lucky number (made only of digits 4 and 7).

Input Format

A single integer $n$ .

Output Format

Print YES if $n$ is nearly lucky, otherwise print NO.

Constraints

$1 \le n \le 10^9$
$n$ is given in decimal form.

Examples

Sample cases returned by the problem API.

Example 1

Input

Output

NO

Explanation

The digits 4 and 7 appear 3 times. Since 3 is not a lucky number, the answer is NO.

Example 2

Input

Output

YES

Explanation

There are 4 lucky digits, and 4 is itself a lucky number, so the answer is YES.

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