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Ahmed loves the letter "Z" very much, and he loves the number of "Z" letters in each string s.
Input
The first line of input contains string s.
Output
Print an integer representing the number of occurrences of the letter "Z". If there is no "Z", type "NO" without the quotes. examples: input:
zzzz
output: 4
input:
codeforces
output:
NO
