issue #9 Nearly Lucky Number

[binarybeast7]

Title - Nearly Lucky Number link - http://codeforces.com/problemset/problem/110/A

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.

Unfortunately, not all numbers are lucky. Petya calls a number nearly lucky if the number of lucky digits in it is a lucky number. He wonders whether number n is a nearly lucky number.

Input The only line contains an integer n (1 ≤ n ≤ 1018).

Please do not use the %lld specificator to read or write 64-bit numbers in С++. It is preferred to use the cin, cout streams or the %I64d specificator.

Output Print on the single line "YES" if n is a nearly lucky number. Otherwise, print "NO" (without the quotes).

Examples

input 40047 output NO

input 7747774 output YES

input 1000000000000000000 output NO

[war-18]

anujrw18 Can you assign this issue to me?

[vaibhv232]

hello sir , assign it to me