B"Let's say that two strings a and b are equal if you can get the string b by cyclically shifting string a . For example, the strings 0100110 and 1100100 are equal, while 1010 and 1100 are not. You are given a binary string s of length n . Its first c characters are 1-s, and its last n - c characters are 0-s. In one operation, you can replace one 0 with 1. Calculate the number of unique strings you can get using no more than k operations. Since the answer may be too large, print it modulo 10^9 + 7 . The first and only line contains three integers n , c and k ( 1 <= n <= 3000 ; 1 <= c <= n ; 0 <= k <= n - c ) -- the length of string s , the length of prefix of 1-s and the maximum number of operations. Print the single integer -- the number of unique strings you can achieve performing no more than k operations, modulo 10^9 + 7 . In the first test case, the only possible string is 1. In the second test case, the possible strings are: 100, 110, and 111. String 101 is equal to 110, so we don't count it. In the third test case, the possible strings are: 10000, 11000, 10100. String 10010 is equal to 10100, and 10001 is equal to 11000. "...