Buggy python submission (verdict: Runtime Error):
N=int(input())
A=list(map(int,input().split()))
B=[0]*(N//2+N%2)
ans=0
ans2=0
if N%2==0:
    for i in range(N):
        if A[i]%2==1 and (A[i]+1)/2<=N/2:
            B[(A[i]-1)//2]+=1
        else:
            print(0)
            exit()
    for i in range((N//2+N%2)):
        if B[i]!=2:
            print(0)
            exit()
    ans=pow(2,N/2)%(pow(10,9)+7)
    ans2=int(ans)
    print(ans2)
elif N%2==1:
    for i in range(N):
        if A[i]%2==0 and A[i]/2<=(N-1)/2:
            B[A[i]//2]+=1
        else:
            print(0)
            exit()
    if B[0]!=1:
        print(0)
        exit()
    for i in range((N//2+N%2)-1):
        if B[i+1]!=2:
            print(0)
            exit()
    ans=pow(2,(N-1)/2)%(pow(10,9)+7)
    ans2=int(ans)
    print(ans2)
else:
    print(0)


Fixed submission:
N=int(input())
A=list(map(int,input().split()))
B=[0]*(N//2+N%2)
IndexCount=0
IndexRe=0
Divider=pow(10,9)+7
ans=1
if N%2==0:
    for i in range(N):
        if A[i]%2==1 and (A[i]+1)/2<=N/2:
            B[(A[i]-1)//2]+=1
        else:
            print(0)
            exit()
    for i in range((N//2+N%2)):
        if B[i]!=2:
            print(0)
            exit()
    IndexCount=int((N/2)//1000)
    IndexRe=int((N/2)%1000)
    for i in range(IndexCount):
        ans=(ans*(pow(2,1000)%Divider))%Divider
    ans=(ans*(pow(2,IndexRe)%Divider))%Divider
    print(ans)
elif N%2==1:
    for i in range(N):
        if A[i]%2==0 and A[i]/2<=(N-1)/2:
            B[A[i]//2]+=1
        else:
            print(0)
            exit()
    if B[0]!=1:
        print(0)
        exit()
    for i in range((N//2+N%2)-1):
        if B[i+1]!=2:
            print(0)
            exit()
    IndexCount=int(((N-1)/2)//1000)
    IndexRe=int(((N-1)/2)%1000)
    for i in range(IndexCount):
        ans=(ans*(pow(2,1000)%Divider))%Divider
    ans=(ans*(pow(2,IndexRe)%Divider))%Divider
    print(ans)
else:
    print(0)

Buggy python submission (verdict: Runtime Error):
N=int(input())
A=list(map(int,input().split()))
B=[0]*(N//2+N%2)
ans=0
ans2=0
if N%2==0:
    for i in range(N-1):
        if A[i]%2==1 and (A[i]+1)/2<=N/2:
            B[(A[i]-1)//2]+=1
        else:
            print(0)
            exit()
    for i in range(len(B)):
        if B[i]!=2:
            print(0)
            exit()
    ans=pow(2,N/2)%(pow(10,9)+7)
    ans2=int(ans)
    print(ans2)
elif N%2==1:
    for i in range(N):
        if A[i]%2==0 and A[i]/2<=(N-1)/2:
            B[A[i]//2]+=1
        else:
            print(0)
            exit()
    if B[0]!=1:
        print(0)
        exit()
    for i in range(len(B)-1):
        if B[i+1]!=2:
            print(0)
            exit()
    ans=pow(2,(N-1)/2)%(pow(10,9)+7)
    ans2=int(ans)
    print(ans2)
else:
    print(0)


Fixed submission:
N=int(input())
A=list(map(int,input().split()))
B=[0]*(N//2+N%2)
IndexCount=0
IndexRe=0
Divider=pow(10,9)+7
ans=1
if N%2==0:
    for i in range(N):
        if A[i]%2==1 and (A[i]+1)/2<=N/2:
            B[(A[i]-1)//2]+=1
        else:
            print(0)
            exit()
    for i in range((N//2+N%2)):
        if B[i]!=2:
            print(0)
            exit()
    IndexCount=int((N/2)//1000)
    IndexRe=int((N/2)%1000)
    for i in range(IndexCount):
        ans=(ans*(pow(2,1000)%Divider))%Divider
    ans=(ans*(pow(2,IndexRe)%Divider))%Divider
    print(ans)
elif N%2==1:
    for i in range(N):
        if A[i]%2==0 and A[i]/2<=(N-1)/2:
            B[A[i]//2]+=1
        else:
            print(0)
            exit()
    if B[0]!=1:
        print(0)
        exit()
    for i in range((N//2+N%2)-1):
        if B[i+1]!=2:
            print(0)
            exit()
    IndexCount=int(((N-1)/2)//1000)
    IndexRe=int(((N-1)/2)%1000)
    for i in range(IndexCount):
        ans=(ans*(pow(2,1000)%Divider))%Divider
    ans=(ans*(pow(2,IndexRe)%Divider))%Divider
    print(ans)
else:
    print(0)

Buggy python submission (verdict: Runtime Error):
N=int(input())
A=list(map(int,input().split()))
B=[0]*(N//2+N%2)
ans=0
ans2=0
if N%2==0:
    for i in range(len(B)):
        if A[i]%2==1 and (A[i]+1)/2<=N/2:
            B[(A[i]-1)//2]+=1
        else:
            print(0)
            exit()
    for i in range(len(B)):
        if B[i]!=2:
            print(0)
            exit()
    ans=pow(2,N/2)%(pow(10,9)+7)
    ans2=int(ans)
    print(ans2)
elif N%2==1:
    for i in range(N):
        if A[i]%2==0 and A[i]/2<=(N-1)/2:
            B[A[i]//2]+=1
        else:
            print(0)
            exit()
    if B[0]!=1:
        print(0)
        exit()
    for i in range(len(B)-1):
        if B[i+1]!=2:
            print(0)
            exit()
    ans=pow(2,(N-1)/2)%(pow(10,9)+7)
    ans2=int(ans)
    print(ans2)
else:
    print(0)


Fixed submission:
N=int(input())
A=list(map(int,input().split()))
B=[0]*(N//2+N%2)
IndexCount=0
IndexRe=0
Divider=pow(10,9)+7
ans=1
if N%2==0:
    for i in range(N):
        if A[i]%2==1 and (A[i]+1)/2<=N/2:
            B[(A[i]-1)//2]+=1
        else:
            print(0)
            exit()
    for i in range((N//2+N%2)):
        if B[i]!=2:
            print(0)
            exit()
    IndexCount=int((N/2)//1000)
    IndexRe=int((N/2)%1000)
    for i in range(IndexCount):
        ans=(ans*(pow(2,1000)%Divider))%Divider
    ans=(ans*(pow(2,IndexRe)%Divider))%Divider
    print(ans)
elif N%2==1:
    for i in range(N):
        if A[i]%2==0 and A[i]/2<=(N-1)/2:
            B[A[i]//2]+=1
        else:
            print(0)
            exit()
    if B[0]!=1:
        print(0)
        exit()
    for i in range((N//2+N%2)-1):
        if B[i+1]!=2:
            print(0)
            exit()
    IndexCount=int(((N-1)/2)//1000)
    IndexRe=int(((N-1)/2)%1000)
    for i in range(IndexCount):
        ans=(ans*(pow(2,1000)%Divider))%Divider
    ans=(ans*(pow(2,IndexRe)%Divider))%Divider
    print(ans)
else:
    print(0)

Buggy python submission (verdict: Runtime Error):
N=int(input())
A=list(map(int,input().split()))
B=[0]*(N//2+N%2)
ans=0
ans2=0
if N%2==0:
    for i in range(N):
        if A[i]%2==1 and (A[i]+1)/2<=N/2:
            B[(A[i]-1)//2]+=1
        else:
            print(0)
            exit()
    for i in range(len(B)):
        if B[i]!=2:
            print(0)
            exit()
    ans=pow(2,N/2)%(pow(10,9)+7)
    ans2=int(ans)
    print(ans2)
elif N%2==1:
    for i in range(N):
        if A[i]%2==0 and A[i]/2<=(N-1)/2:
            B[A[i]//2]+=1
        else:
            print(0)
            exit()
    if B[0]!=1:
        print(0)
        exit()
    for i in range(len(B)-1):
        if B[i+1]!=2:
            print(0)
            exit()
    ans=pow(2,(N-1)/2)%(pow(10,9)+7)
    ans2=int(ans)
    print(ans2)
else:
    print(0)

Fixed submission:
N=int(input())
A=list(map(int,input().split()))
B=[0]*(N//2+N%2)
IndexCount=0
IndexRe=0
Divider=pow(10,9)+7
ans=1
if N%2==0:
    for i in range(N):
        if A[i]%2==1 and (A[i]+1)/2<=N/2:
            B[(A[i]-1)//2]+=1
        else:
            print(0)
            exit()
    for i in range((N//2+N%2)):
        if B[i]!=2:
            print(0)
            exit()
    IndexCount=int((N/2)//1000)
    IndexRe=int((N/2)%1000)
    for i in range(IndexCount):
        ans=(ans*(pow(2,1000)%Divider))%Divider
    ans=(ans*(pow(2,IndexRe)%Divider))%Divider
    print(ans)
elif N%2==1:
    for i in range(N):
        if A[i]%2==0 and A[i]/2<=(N-1)/2:
            B[A[i]//2]+=1
        else:
            print(0)
            exit()
    if B[0]!=1:
        print(0)
        exit()
    for i in range((N//2+N%2)-1):
        if B[i+1]!=2:
            print(0)
            exit()
    IndexCount=int(((N-1)/2)//1000)
    IndexRe=int(((N-1)/2)%1000)
    for i in range(IndexCount):
        ans=(ans*(pow(2,1000)%Divider))%Divider
    ans=(ans*(pow(2,IndexRe)%Divider))%Divider
    print(ans)
else:
    print(0)

Buggy python submission (verdict: Runtime Error):
N=int(input())
A=list(map(int,input().split()))
B=[0]*(N//2+N%2)
ans=0
ans2=0
if N%2==0:
    for i in range(N):
        if A[i]%2==1 and (A[i]+1)/2<=N/2:
            B[(A[i]-1)//2]+=1
        else:
            print(0)
            exit()
    for i in range(len(B)):
        if B[i]!=2:
            print(0)
            exit()
    ans=pow(2,N/2)%(pow(10,9)+7)
    ans2=int(ans)
    print(ans2)
elif N%2==1:
    for i in range(N):
        if A[i]%2==0 and A[i]/2<=(N-1)/2:
            B[A[i]//2]+=1
        else:
            print(0)
            exit()
    if B[0]!=1:
        print(0)
        exit()
    for i in range(len(B)-1):
        if B[i+1]!=2:
            print(0)
            exit()
    ans=pow(2,(N-1)/2)%(pow(10,9)+7)
    ans2=int(ans)
    print(ans2))
else:
    print(0)

Fixed submission:
N=int(input())
A=list(map(int,input().split()))
B=[0]*(N//2+N%2)
IndexCount=0
IndexRe=0
Divider=pow(10,9)+7
ans=1
if N%2==0:
    for i in range(N):
        if A[i]%2==1 and (A[i]+1)/2<=N/2:
            B[(A[i]-1)//2]+=1
        else:
            print(0)
            exit()
    for i in range((N//2+N%2)):
        if B[i]!=2:
            print(0)
            exit()
    IndexCount=int((N/2)//1000)
    IndexRe=int((N/2)%1000)
    for i in range(IndexCount):
        ans=(ans*(pow(2,1000)%Divider))%Divider
    ans=(ans*(pow(2,IndexRe)%Divider))%Divider
    print(ans)
elif N%2==1:
    for i in range(N):
        if A[i]%2==0 and A[i]/2<=(N-1)/2:
            B[A[i]//2]+=1
        else:
            print(0)
            exit()
    if B[0]!=1:
        print(0)
        exit()
    for i in range((N//2+N%2)-1):
        if B[i+1]!=2:
            print(0)
            exit()
    IndexCount=int(((N-1)/2)//1000)
    IndexRe=int(((N-1)/2)%1000)
    for i in range(IndexCount):
        ans=(ans*(pow(2,1000)%Divider))%Divider
    ans=(ans*(pow(2,IndexRe)%Divider))%Divider
    print(ans)
else:
    print(0)

Buggy python submission (verdict: Runtime Error):
N=int(input())
A=list(map(int,input().split()))
B=[0]*(N//2+N%2)
if N%2==0:
    for i in range(N):
        if A[i]%2==1 and (A[i]+1)/2<=N/2:
            B[(A[i]-1)//2]+=1
        else:
            print(0)
            exit()
    for i in range(len(B)):
        if B[i]!=2:
            print(0)
            exit()
    print(int(pow(2,N/2)%(pow(10,9)+7)))
elif N%2==1:
    for i in range(N):
        if A[i]%2==0 and A[i]/2<=(N-1)/2:
            B[A[i]//2]+=1
        else:
            print(0)
            exit()
    if B[0]!=1:
        print(0)
        exit()
    for i in range(len(B)-1):
        if B[i+1]!=2:
            print(0)
            exit()
    print(int(pow(2,(N-1)/2)%(pow(10,9)+7)))
else:
    print(0)

Fixed submission:
N=int(input())
A=list(map(int,input().split()))
B=[0]*(N//2+N%2)
IndexCount=0
IndexRe=0
Divider=pow(10,9)+7
ans=1
if N%2==0:
    for i in range(N):
        if A[i]%2==1 and (A[i]+1)/2<=N/2:
            B[(A[i]-1)//2]+=1
        else:
            print(0)
            exit()
    for i in range((N//2+N%2)):
        if B[i]!=2:
            print(0)
            exit()
    IndexCount=int((N/2)//1000)
    IndexRe=int((N/2)%1000)
    for i in range(IndexCount):
        ans=(ans*(pow(2,1000)%Divider))%Divider
    ans=(ans*(pow(2,IndexRe)%Divider))%Divider
    print(ans)
elif N%2==1:
    for i in range(N):
        if A[i]%2==0 and A[i]/2<=(N-1)/2:
            B[A[i]//2]+=1
        else:
            print(0)
            exit()
    if B[0]!=1:
        print(0)
        exit()
    for i in range((N//2+N%2)-1):
        if B[i+1]!=2:
            print(0)
            exit()
    IndexCount=int(((N-1)/2)//1000)
    IndexRe=int(((N-1)/2)%1000)
    for i in range(IndexCount):
        ans=(ans*(pow(2,1000)%Divider))%Divider
    ans=(ans*(pow(2,IndexRe)%Divider))%Divider
    print(ans)
else:
    print(0)

Buggy python submission (verdict: Runtime Error):
N=int(input())
A=list(map(int,input().split()))
B=[0]*(N//2+N%2)
if N%2==0:
    for i in range(N):
        if A[i]%2==1 and (A[i]+1)/2<=N/2:
            B[(A[i]-1)//2]+=1
        else:
            print(0)
            exit()
    for i in range(len(B)):
        if B[i]!=2:
            print(0)
            exit()
    print(int(pow(2,N/2)%(pow(10,9)+7)))
elif N%2==1:
    for i in range(N):
        if A[i]%2==0 and A[i]/2<=(N+1)/2:
            B[A[i]//2]+=1
        else:
            print(0)
            exit()
    if B[0]!=1:
        print(0)
        exit()
    for i in range(len(B)-1):
        if B[i+1]!=2:
            print(0)
            exit()
    print(int(pow(2,(N-1)/2)%(pow(10,9)+7)))
else:
    print(0)


Fixed submission:
N=int(input())
A=list(map(int,input().split()))
B=[0]*(N//2+N%2)
IndexCount=0
IndexRe=0
Divider=pow(10,9)+7
ans=1
if N%2==0:
    for i in range(N):
        if A[i]%2==1 and (A[i]+1)/2<=N/2:
            B[(A[i]-1)//2]+=1
        else:
            print(0)
            exit()
    for i in range((N//2+N%2)):
        if B[i]!=2:
            print(0)
            exit()
    IndexCount=int((N/2)//1000)
    IndexRe=int((N/2)%1000)
    for i in range(IndexCount):
        ans=(ans*(pow(2,1000)%Divider))%Divider
    ans=(ans*(pow(2,IndexRe)%Divider))%Divider
    print(ans)
elif N%2==1:
    for i in range(N):
        if A[i]%2==0 and A[i]/2<=(N-1)/2:
            B[A[i]//2]+=1
        else:
            print(0)
            exit()
    if B[0]!=1:
        print(0)
        exit()
    for i in range((N//2+N%2)-1):
        if B[i+1]!=2:
            print(0)
            exit()
    IndexCount=int(((N-1)/2)//1000)
    IndexRe=int(((N-1)/2)%1000)
    for i in range(IndexCount):
        ans=(ans*(pow(2,1000)%Divider))%Divider
    ans=(ans*(pow(2,IndexRe)%Divider))%Divider
    print(ans)
else:
    print(0)

Buggy python submission (verdict: Runtime Error):
N=int(input())
A=list(map(int,input().split()))
B=[0]*(N//2+N%2)
if N%2==0:
    for i in range(N):
        if A[i]%2==1 and (A[i]-1)/2<=N/2:
            B[(A[i]-1)//2]+=1
        else:
            print(0)
            exit()
    for i in range(len(B)):
        if B[i]!=2:
            print(0)
            exit()
    print(int(pow(2,N/2)%(pow(10,9)+7)))
elif N%2==1:
    for i in range(N):
        if A[i]%2==0 and A[i]/2<=(N+1)/2:
            B[A[i]//2]+=1
        else:
            print(0)
            exit()
    if B[0]!=1:
        print(0)
        exit()
    for i in range(len(B)-1):
        if B[i+1]!=2:
            print(0)
            exit()
    print(int(pow(2,(N-1)/2)%(pow(10,9)+7)))
else:
    print(0)

Fixed submission:
N=int(input())
A=list(map(int,input().split()))
B=[0]*(N//2+N%2)
IndexCount=0
IndexRe=0
Divider=pow(10,9)+7
ans=1
if N%2==0:
    for i in range(N):
        if A[i]%2==1 and (A[i]+1)/2<=N/2:
            B[(A[i]-1)//2]+=1
        else:
            print(0)
            exit()
    for i in range((N//2+N%2)):
        if B[i]!=2:
            print(0)
            exit()
    IndexCount=int((N/2)//1000)
    IndexRe=int((N/2)%1000)
    for i in range(IndexCount):
        ans=(ans*(pow(2,1000)%Divider))%Divider
    ans=(ans*(pow(2,IndexRe)%Divider))%Divider
    print(ans)
elif N%2==1:
    for i in range(N):
        if A[i]%2==0 and A[i]/2<=(N-1)/2:
            B[A[i]//2]+=1
        else:
            print(0)
            exit()
    if B[0]!=1:
        print(0)
        exit()
    for i in range((N//2+N%2)-1):
        if B[i+1]!=2:
            print(0)
            exit()
    IndexCount=int(((N-1)/2)//1000)
    IndexRe=int(((N-1)/2)%1000)
    for i in range(IndexCount):
        ans=(ans*(pow(2,1000)%Divider))%Divider
    ans=(ans*(pow(2,IndexRe)%Divider))%Divider
    print(ans)
else:
    print(0)

Buggy python submission (verdict: Runtime Error):
N=int(input())
A=list(map(int,input().split()))
B=[0]*(N//2+N%2)
if N%2==0:
    for i in range(N):
        if A[i]%2==1 and (A[i]-1)/2<=N/2:
            B[(A[i]-1)//2]+=1
        else:
            print(0)
            exit()
    for i in range(len(B)):
        if B[i]!=2:
            print(0)
            exit()
    print(int(pow(2,N/2)%(pow(10,9)+7)))
elif N%2==1:
    for i in range(N):
        if A[i]%2==0 and A[i]/2<=N+1/2:
            B[A[i]//2]+=1
        else:
            print(0)
            exit()
    if B[0]!=1:
        print(0)
        exit()
    for i in range(len(B)-1):
        if B[i+1]!=2:
            print(0)
            exit()
    print(int(pow(2,(N-1)/2)%(pow(10,9)+7)))
else:
    print(0)

Fixed submission:
N=int(input())
A=list(map(int,input().split()))
B=[0]*(N//2+N%2)
IndexCount=0
IndexRe=0
Divider=pow(10,9)+7
ans=1
if N%2==0:
    for i in range(N):
        if A[i]%2==1 and (A[i]+1)/2<=N/2:
            B[(A[i]-1)//2]+=1
        else:
            print(0)
            exit()
    for i in range((N//2+N%2)):
        if B[i]!=2:
            print(0)
            exit()
    IndexCount=int((N/2)//1000)
    IndexRe=int((N/2)%1000)
    for i in range(IndexCount):
        ans=(ans*(pow(2,1000)%Divider))%Divider
    ans=(ans*(pow(2,IndexRe)%Divider))%Divider
    print(ans)
elif N%2==1:
    for i in range(N):
        if A[i]%2==0 and A[i]/2<=(N-1)/2:
            B[A[i]//2]+=1
        else:
            print(0)
            exit()
    if B[0]!=1:
        print(0)
        exit()
    for i in range((N//2+N%2)-1):
        if B[i+1]!=2:
            print(0)
            exit()
    IndexCount=int(((N-1)/2)//1000)
    IndexRe=int(((N-1)/2)%1000)
    for i in range(IndexCount):
        ans=(ans*(pow(2,1000)%Divider))%Divider
    ans=(ans*(pow(2,IndexRe)%Divider))%Divider
    print(ans)
else:
    print(0)

Buggy python submission (verdict: Runtime Error):
if N%2==0:
    for i in range(N):
        if A[i]%2==1 and (A[i]-1)/2<=N/2:
            B[(A[i]-1)//2]+=1
        else:
            print(0)
            exit()
    for i in range(len(B)):
        if B[i]!=2:
            print(0)
            exit()
    print(int(pow(2,N/2)%(pow(10,9)+7)))
elif N%2==1:
    for i in range(N):
        if A[i]%2==0 and A[i]/2<=N+1/2:
            B[A[i]//2]+=1
        else:
            print(0)
            exit()
    if B[0]!=1:
        print(0)
        exit()
    for i in range(len(B)-1):
        if B[i+1]!=2:
            print(0)
            exit()
    print(int(pow(2,(N-1)/2)%(pow(10,9)+7)))
else:
    print(0)

Fixed submission:
N=int(input())
A=list(map(int,input().split()))
B=[0]*(N//2+N%2)
IndexCount=0
IndexRe=0
Divider=pow(10,9)+7
ans=1
if N%2==0:
    for i in range(N):
        if A[i]%2==1 and (A[i]+1)/2<=N/2:
            B[(A[i]-1)//2]+=1
        else:
            print(0)
            exit()
    for i in range((N//2+N%2)):
        if B[i]!=2:
            print(0)
            exit()
    IndexCount=int((N/2)//1000)
    IndexRe=int((N/2)%1000)
    for i in range(IndexCount):
        ans=(ans*(pow(2,1000)%Divider))%Divider
    ans=(ans*(pow(2,IndexRe)%Divider))%Divider
    print(ans)
elif N%2==1:
    for i in range(N):
        if A[i]%2==0 and A[i]/2<=(N-1)/2:
            B[A[i]//2]+=1
        else:
            print(0)
            exit()
    if B[0]!=1:
        print(0)
        exit()
    for i in range((N//2+N%2)-1):
        if B[i+1]!=2:
            print(0)
            exit()
    IndexCount=int(((N-1)/2)//1000)
    IndexRe=int(((N-1)/2)%1000)
    for i in range(IndexCount):
        ans=(ans*(pow(2,1000)%Divider))%Divider
    ans=(ans*(pow(2,IndexRe)%Divider))%Divider
    print(ans)
else:
    print(0)

Buggy python submission (verdict: Runtime Error):
N=int(input())
A=list(map(int,input().split()))
B=[0]*(N//2+N%2)
if N%2==0:
    for i in range(N):
        if A[i]%2==1 and (A[i]-1)/2<=N/2:
            B[(A[i]-1)//2]+=1
        else:
            print(0)
            exit()
    for i in range(len(B)):
        if B[i]!=2:
            print(0)
            exit()
    print(int(pow(2,N/2)%(pow(10,9)+7)))
else:
    for i in range(N):
        if A[i]%2==0 and A[i]/2<=N+1/2:
            B[A[i]//2]+=1
        else:
            print(0)
            exit()
    if B[0]!=1:
        print(0)
        exit()
    for i in range(len(B)-1):
        if B[i+1]!=2:
            print(0)
            exit()
    print(int(pow(2,(N-1)/2)%(pow(10,9)+7)))

Fixed submission:
N=int(input())
A=list(map(int,input().split()))
B=[0]*(N//2+N%2)
IndexCount=0
IndexRe=0
Divider=pow(10,9)+7
ans=1
if N%2==0:
    for i in range(N):
        if A[i]%2==1 and (A[i]+1)/2<=N/2:
            B[(A[i]-1)//2]+=1
        else:
            print(0)
            exit()
    for i in range((N//2+N%2)):
        if B[i]!=2:
            print(0)
            exit()
    IndexCount=int((N/2)//1000)
    IndexRe=int((N/2)%1000)
    for i in range(IndexCount):
        ans=(ans*(pow(2,1000)%Divider))%Divider
    ans=(ans*(pow(2,IndexRe)%Divider))%Divider
    print(ans)
elif N%2==1:
    for i in range(N):
        if A[i]%2==0 and A[i]/2<=(N-1)/2:
            B[A[i]//2]+=1
        else:
            print(0)
            exit()
    if B[0]!=1:
        print(0)
        exit()
    for i in range((N//2+N%2)-1):
        if B[i+1]!=2:
            print(0)
            exit()
    IndexCount=int(((N-1)/2)//1000)
    IndexRe=int(((N-1)/2)%1000)
    for i in range(IndexCount):
        ans=(ans*(pow(2,1000)%Divider))%Divider
    ans=(ans*(pow(2,IndexRe)%Divider))%Divider
    print(ans)
else:
    print(0)