题目描述
Little Pandey has N colorless balls.
His best friend GJ has K colors, numbered from 1 to K.
Little Pandey assigns to GJ the task of coloring each ball, as GJ is a little free these days.
For the i-th ball GJ chooses color Ci.
But, Little Pandey is tired and bored after the trip.
He decides to find the total number of some special subsets of balls - subsets containing balls of at most M distinct colors.
This task is too complicated to handle for Pandey's tired mind, so he asks for your help, since he cannot expect a lot of help from GJ!
Input format:
The first line of the input consists of three integers N, K and M. The next line consists of N integers C1 , C2 ... CN denoting colors of balls.
Output format:
Print the total number of subsets such that each subset contains balls of at most M distinct colors. Output it modulus 10^9 + 7, i.e., 1000000007.
Constraints:
1 ≤ K, N ≤ 5*10^5
1≤ M ≤ 10
1 ≤ Ci ≤ K
SAMPLE INPUT
4 3 2
3 1 2 3
SAMPLE OUTPUT
13
Explanation
There are 2^4 = 16 possible subsets and 13 of them satisfy the given condition (a subset must contain balls of at most M = 2 distinct colors).
These 13 subsets are {} , {1} , {2} , {3} , {4} , {1,2} , {1,3} , {1,4} , {1,4,2} , {1,4,3} , {2,3} , {2,4} , {3,4}
Numbers in braces denote indices of balls.
输入格式
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输出格式
见题面