Repeated Substring Checker

This problem requires you to determine if there exists a substring of a given length \( k \) that appears at least twice in a given string \( s \). The substring occurrences must be at different positions in the string; note that overlapping occurrences are allowed.

Example: For the string "abcabc" with \( k=3 \), the substring "abc" appears twice, so the answer is YES.

Task: Read the input from standard input. If a substring of length \( k \) exists at least twice, print YES. Otherwise, print NO.

Note: The condition for \( k \) is expressed as \(1 \leq k \leq |s|\), where \(|s|\) is the length of the string.

inputFormat

The input consists of two lines. The first line contains the string \( s \) (which may be empty). The second line contains the integer \( k \).

outputFormat

Output a single line with either YES if there exists a substring of length \( k \) that appears at least twice, or NO otherwise.

## sample

abcabc
3

YES

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