from itertools import combinations
import math
def nCr(n,r):
    f=math.factorial
    return f(n)//f(r)//f(n-r)

N,K=map(int,input().split(" "))
A=list(map(int,input().split(" ")))
B=list(combinations(A,K))

suma=[]

for x in range(len(B)):
    s=1
    for y in range(K):
        if(B[x][y]<4):
           c=1
        else:
           c=nCr(B[x][y],4)+1
        s=s*c     
    suma.append(s)
print(sum(suma)%(10**9 + 7))