N=int(input())
A=list(map(int,input().split()))
ANS=1
B=sorted(A)
C=1
X=1
for i in range(1,N):
  if B[i-1]==B[i]:
    C+=1
    X*=C
  else:
    C=1
  ANS*=(i+1)
print(ANS//X)