Harryxun/stf_run huggingface dataset:
Ans = "A"
while True:
    
    Pos = list(map(str,input().split(",")))
    if Pos == ['']:
        print(Ans)
        break
    if Ans in Pos:
        Ans = Pos[((Pos.index(Ans)) + 1) % 2]

### FIXED CODE ###

Ans = "A"
while True:
    try:
        Pos = list(map(str,input().split(",")))
        if Pos == ['']:
            print(Ans)
            break
        if Ans in Pos:
            Ans = Pos[((Pos.index(Ans)) + 1) % 2]
    except:
        print(Ans)
        break
N = int(input())
S = input()
sint = [0]
prev = S[0]
DEBUG = False
def dbg(*something):
    if DEBUG:
        print(*something)

for s in S:
    if prev == s:
        sint[-1] = sint[-1] + 1
    else:
        prev = s
        sint.append(1)
if len(sint) % 2 == 1:
    if S[0] == '#':
        sint = [0] + sint
    else:
        sint.append(0)
elif S[0] == '#':
    sint = [0] + sint + [0]
dbg(sint)

def count2(numSB,numSW):
    dbg('len:',len(sint))
    if len(sint) < 2:
        return 0
    sint.pop(0)
    sint.pop()
    
    if len(sint) < 2:
        return 0
    b = sint.pop(0)
    w = sint.pop()
    
    numSR =  b + w
    dbg(numSB,numSW,numSR)
    if numSB <= numSW and numSB <= numSR:
        return numSB
    elif numSW <= numSB and numSW <= numSR:
        return numSW
    else:
        return numSR + count2(numSB+b,numSW+w)
    # if numSB <= numSW :
    #     return numSB
    # else:
    #     return numSW
    
    

# def count(_S,_numSW,_numSB):
#     _S = _S.lstrip('.').rstrip('#')
#     if len(_S) == 0 :
#         return 0
#     numSW = _S.count('.')
#     numSB = _S.count('#')
#     SR = _S.lstrip('#').rstrip('.')
#     numSR = len(_S) - len(SR)
#     if numSW <= numSB and numSW <= numSR:
#         return numSW
#     elif numSB <= numSW and numSB <= numSR:
#         return numSB
#     else:
#         return numSR + count(SR)


numSB = 0
numSW = 0
for i,v in enumerate(sint):
    if i % 2 == 1:
        numSB = numSB + v
    else:
        numSW = numSW + v
#print(sint)
#print(sint,numSB,numSW,count2(numSB,numSW))
numSR = count2(numSB,numSW)
dbg('numSW:',numSW)
dbg('numSB',numSB)
dbg('numSR',numSR)
print(min(numSB,numSW,numSR))
'''
22
#####.....####..###...####....#.#.#
'''
# #intS = []
# def xor(A,B):
#     #print(A)
#     #print(B)
#     num = 0
#     for i in range(len(A)):
        
#         if A[i]!=B[i] :
#             num = num + 1
#     return num
# # for s in S :
# #     intS.append(0 if s=='.' else 1)
# minC = N

# mask = ['#' for j in range(len(S) + 1)]
# for i in range(len(S) + 1):
#     mask[i] = '.'
#     c = xor(mask[1::],S)
#     if c < minC:
#         minC = c

# print(minC)
# # def dl(_S):


# #     l = '.'
# #     r = '#'
    
# #     _S = _S.lstrip(l).rstrip(r)
# #     print(_S)
# #     if len(_S) == 0:
# #         return 0
# #     _S2W = _S.lstrip(r)
# #     _S2B = _S.rstrip(l)
# #     _S2 =  _S2W if len(_S2W) <= len(_S2B) else _S2B
# #     return len(_S) - len(_S2) + dl(_S2)
# # print(dl(S))






### FIXED CODE ###

_ = input()
S = input()
numc = S.count('.')
numcmin = numc
for s in S:
    if s == '#':
        numc = numc + 1
    else:
        numc = numc -1
        if numc < numcmin:
            numcmin = numc
print(numcmin)
N, Q = map(int, input().split())
d = [[] for i in range(N)]

for i in range(N-1):
    a, b = map(int, input().split())
    a -= 1
    b -= 1
    d[b].append(a)
    d[a].append(b)

ans = [0 for i in range(N)]

for i in range(Q):
    p, x = map(int, input().split())
    p -= 1
    ans[p] += x

def dfs(cur, parent):
    for child in d[cur]:
        if child != parent
            ans[child] += ans[cur]
            dfs(child,car)
dfs(0,-1) 

print(*ans)

### FIXED CODE ###

N, Q = map(int, input().split())
d = [0 for i in range(N)]

for i in range(N-1):
    a, b = map(int, input().split())
    a -= 1
    b -= 1
    d[b] = a
ans = [0 for i in range(N)]

for i in range(Q):
    p, x = map(int, input().split())
    p -= 1
    ans[p] += x

for i in range(1, N):
    ans[i] += ans[d[i]]

print(*ans)
S=input()
flag=False

if S[0]=="A":
  if S[2:-1].count("C")==1:
    pos=S.find("C")
    T=S[1:pos]+S[pos+1:]
    if T.islower():
      print("AC")
      flag=True
      
if flag=False:
  print("WA")

### FIXED CODE ###

S=input()
flag=False

if S[0]=="A":
  if S[2:-1].count("C")==1:
    pos=S.find("C")
    T=S[1:pos]+S[pos+1:]
    if T.islower():
      print("AC")
      flag=True
      
if flag==False:
  print("WA")
n = int(input())
for i in range(n):
    k = input().split()
    if k[0] == 'S':
        for i in range(1,14):
            if int(k[1])==i:
                continue
            else:
                s = list()
                s.append(i)
                s.sort()
                sl = len(s)
    if k[0] == 'H':
        for i in range(1,14):
            if int(k[1])==i:
                continue
            else:
                h = list()
                h.append(i)
                h.sort()
                hl = len(h)
    if k[0] == 'C':
        for i in range(1,14):
            if int(k[1])==i:
                continue
            else:
                c = list()
                c.append(i)
                c.sort()
                cl = len(c)
    if k[0] == 'D':
        for i in range(1,14):
            if int(k[1])==i:
                continue
            else:
                d = list()
                d.append(i)
                d.sort()
                dl = len(d)
                
for i in range(1,sl):
    print('S {0}'.format(s[i]))
    
for i in range(1,hl+1):
    print('H {0}'.format(h[i]))
 
for i in range(1,dl+1):
    print('D {0}'.format(d[i])) 

for i in range(1,cl+1):
    print('C {0}'.format(c[i]))


### FIXED CODE ###

n = int(input())
S = [1,2,3,4,5,6,7,8,9,10,11,12,13]
C = [1,2,3,4,5,6,7,8,9,10,11,12,13]
H = [1,2,3,4,5,6,7,8,9,10,11,12,13]
D = [1,2,3,4,5,6,7,8,9,10,11,12,13]

for i in range(n):
    variations,number = input().split()
    if variations == 'S':
        S.remove(int(number))
    if variations == 'C':
        C.remove(int(number))
    if variations == 'H':
        H.remove(int(number))
    if variations == 'D':
        D.remove(int(number))

for i in range(len(S)):
    print('{} {}'.format('S',S[i]))

for i in range(len(H)):
    print('{} {}'.format('H',H[i]))

for i in range(len(C)):
    print('{} {}'.format('C',C[i]))

for i in range(len(D)):
    print('{} {}'.format('D',D[i]))
N = int(input())
A = list(map(int, input().split()))

while 0 in A:
    A.remove(0)

A_ = list(set(A))
A_.sort()
for i in range(len(A_) - 1):
    if A_[i+1] == A_[i]+2:
        judge = 1
    else:
        judge = 0

if len(set(A)) == len(A)/2 and judge:
    print(2 ** (len(A) // 2))
else:
    print(0)

### FIXED CODE ###

N = int(input())
A = list(map(int, input().split()))
judge = 1
while 0 in A:
    A.remove(0)

A_ = list(set(A))
A_.sort()
for i in range(len(A_) - 1):
    if A_[i+1] == A_[i]+2:
        judge = 1
    else:
        judge = 0

if len(set(A)) == len(A)/2 and judge:
    print((2 ** (len(A) // 2)) % (10**9 +7))
else:
    print(0)
n=int(input())
a=[]
for i in range(n):
    a.append(int(input()))
c=max(a)
check=False
for i in range(n):
    if a[i]==c&&check==False:
        b=a[:i]+a[i+1:]
        d=max(b)
        print(d)
    elif a[i]==c&&check==True:
        print(d)
    else:
        print(c)

### FIXED CODE ###

r=int(input())
print(3*r**2)
s=0
A=input().split()
n=(int)(A[0])
t=(int)(A[1])
x=[0 for i in range(2*n)]
for i in range(n):
    B=input().split()
    k=2*i
    x[k]=(B[0])
    x[k+1]=(int)(B[1])
while len(x)>0:
    s=x[1]-t
    if s>0: 
        sum+=t
        x.append(x[0])
        x.append(s)
        del x[0]
        del x[0]
    if s<=0:
        sum+=x[1]
        print( x[0],sum)
        del x[0]
        del x[0]



### FIXED CODE ###

sum=0
s=0
A=input().split()
n=(int)(A[0])
t=(int)(A[1])
x=[0 for i in range(2*n)]
for i in range(n):
    B=input().split()
    k=2*i
    x[k]=(B[0])
    x[k+1]=(int)(B[1])
while len(x)>0:
    s=x[1]-t
    if s>0: 
        sum+=t
        x.append(x[0])
        x.append(s)
        del x[0]
        del x[0]
    if s<=0:
        sum+=x[1]
        print( x[0],sum)
        del x[0]
        del x[0]
def solve():
    N, K = map(int, input().split())
    X = list(map(int, input().split()))
    if 0 in X:
        N -= 1
        K -= 1
        X.remove(0)
    ans = 10**9
    for i in range(N-K+1):
        if X[i+K-1]<=0:
            p = -X[i]
        elif X[i]>=0:
            p = X[i+K-1]
        else:
            p = X[i+K-1]-X[i]+min(X[i+K-1],abs(X[i]))
        ans = min(ans,p)
    return ans
print(solve())

### FIXED CODE ###

def solve():
    N, K = map(int, input().split())
    X = list(map(int, input().split()))
    if 0 in X:
        N -= 1
        K -= 1
        if K == 0:
            return 0
        X.remove(0)
    ans = 10**9
    for i in range(N-K+1):
        if X[i+K-1]<=0:
            p = -X[i]
        elif X[i]>=0:
            p = X[i+K-1]
        else:
            p = X[i+K-1]-X[i]+min(X[i+K-1],abs(X[i]))
        ans = min(ans,p)
    return ans
print(solve())
`r`````````````````. ````````@|@|@|@|@|@|@|@|@|@|@|@|i

### FIXED CODE ###

s = input()
print(s[:4] + " " + s[4:])
s = int(input())

fact = [1] * s
inv = [1] * s
invf = [1] * s
for i in range(2, s):
  fact[i] = fact[i-1] * i % mod
  inv[i] = -(p // i) * inv[p % i] % mod
  invf[i] = invf[i-1] * inv[i] % mod

count = 0
rest = s
for n in range(1, (s + 2) // 3):
  rest -= 3
  count = (count + inv[rest + n - 1] * invf[rest] * invf[n - 1]) % mod
print(count)

### FIXED CODE ###

s = int(input())
mod = 10 ** 9 + 7

fact = [1] * s
inv = [1] * s
invf = [1] * s
for i in range(2, s):
  fact[i] = fact[i-1] * i % mod
  inv[i] = -(mod // i) * inv[mod % i] % mod
  invf[i] = invf[i-1] * inv[i] % mod

count = 0
rest = s
for n in range(1, s // 3 + 1):
  rest -= 3
  count = (count + fact[rest + n - 1] * invf[rest] * invf[n - 1]) % mod
print(count)
#!/usr/bin python3
# -*- coding: utf-8 -*-

from collections import deque

N, C = map(int,input().split())
Mx = 10**5+1
sch = [0]*Mx
plist = [[] for _ in range(C)]
for _ in range(N):
    s, t, c = map(int,input().split())
    plist[c-1].append((s,t))
for p in plist:
    if len(p)==0:
        continue
    p.sort()
    prevt = 0
    for s, t in p:
        sch[s] += 1
        sch[t+1] -= 1
        if prevt == s:
            sch[prevt+1] += 1
            sch[s] -= 1
        prevt = t

for i in range(1,Mx):
    sch[i]+=sch[i-1]

print(max(sch))


### FIXED CODE ###

#!/usr/bin python3
# -*- coding: utf-8 -*-

from collections import deque

N, C = map(int,input().split())
Mx = 10**5+1
sch = [[0]*Mx for _ in range(C)]
scht = [0]*Mx
plist = [[] for _ in range(C)]
for _ in range(N):
    s, t, c = map(int,input().split())
    plist[c-1].append((s,t))
for c, p in enumerate(plist):
    p.sort()
    prevt = 0
    for s, t in p:
        if prevt == s:
            sch[c][prevt] = 0
        else:
            sch[c][s] = 1
        sch[c][t] = -1
        prevt = t
    for i in range(1, Mx):
        if sch[c][i]==1:
            scht[i-1]+=1
        if sch[c][i]==-1:
            scht[i]-=1

for i in range(1, Mx):
    scht[i] += scht[i-1]

print(max(scht))
n = int(input())
a = [int(x) for x in input().split()]

res = 0
x = 0
for i in range(n-1):
    x += a[i]
    sign = (x // abs(x)) * (-1)
    tmp = sign - (x + a[i+1])
    if sign < 0:
        tmp = min(tmp, 0)
    else:
        tmp = max(tmp, 0)
    res += abs(tmp)
    a[i+1] += tmp

print(res)

### FIXED CODE ###

n = int(input())
arr = [0] + [int(x) for x in input().split()]

def exec(sign):
    a = [x for x in arr]
    res = 0

    x = 0
    for i in range(n):
        x += a[i]
        tmp = sign - (x + a[i+1])
        if sign < 0:
            tmp = min(tmp, 0)
        else:
            tmp = max(tmp, 0)
        res += abs(tmp)
        a[i+1] += tmp
        sign *= (-1)
    return res

print(min(exec(1), exec(-1)))
import math
from functools import reduce

def lcm_base(x, y):
    return (x * y) // math.gcd(x, y)

def lcm_list(numbers):
    return reduce(lcm_base, numbers, 1)

P = 10**9 + 7
N = 10000
inv_t = [0]+[1]
for i in range(2,N):
    inv_t += [inv_t[P % i] * (P - int(P / i)) % P]

n=int(input())
A=[int(i) for i in input().split()]

#kyodai=lcm_list(A)
kyodai=A[0]
for i in range(1,n):
    kyodai=lcm_base(kyodai,A[i])

ans=0

for i in range(n):
    ans+=kyodai*inv_t[A[i]]
    ans=ans%P

print(ans)

### FIXED CODE ###

def gcd(a,b):
    for xx in range(1000001):
        a,b=b,a%b
        if b==0:
            break
    return a

def lcm_base(x, y):
    return (x * y) // gcd(x, y)

P = 10**9 + 7
N = 1000001
inv_t = [0]+[1]
for i in range(2,N):
    inv_t += [inv_t[P % i] * (P - int(P / i)) % P]

n=int(input())
A=[int(i) for i in input().split()]

#kyodai=lcm_list(A)
kyodai=A[0]
for i in range(1,n):
    kyodai=lcm_base(kyodai,A[i])

ans=0

for i in range(n):
    ans+=inv_t[A[i]]
    ans=ans%P
ans=ans*kyodai
ans=ans%P

print(ans)
import heapq
import math
N,K=map(int,input().split())
A=list(map(int,input().split()))
hq=[]
for i in A:
    heapq.heappush(hq,-i)
while K>0:
    t1=heapq.heappop(hq)
    t2=heapq.heappop(hq)
    if t1==t2 or K<3:
        heapq.heappush(hq,t1/2)
        heapq.heappush(hq,t1/2)
        heapq.heappush(hq,t2)
        K-=1
    else:
        heapq.heappush(hq,t1/3)
        heapq.heappush(hq,t1/3)
        heapq.heappush(hq,t1/3)
        heapq.heappush(hq,t2)
        K-=2
print(math.ceil(-heapq.heappop(hq)))

### FIXED CODE ###

N,K=map(int,input().split())
A=list(map(int,input().split()))
low=0
high=max(A)
while high-low>1:
    mid=(low+high)//2
    cnt=0
    for i in A:
        cnt+=(i-1)//mid
    if cnt>K:
        low=mid
    else:
        high=mid
print(high)
h,w,m=map(int, input().split())
a = [[0 for j in range(w)] for i in range(h)]
for i in range(m):
	x,y=map(int, input().split())
	a[x-1][y-1]+=1
hc=[0 for i in range(w)]
wc=[0 for i in range(h)]
for i in range(w):
	for j in range(h):
		hc[i] += a[j][i]
for i in range(h):
	for j in range(w):
		wc[i] += a[i][j]
ans=0
for i in range(len(hc)):
	for j in range(len(wc)):
		if a[i][j]==1:
			if ans<hc[i]+wc[j]-1:
				ans=hc[i]+wc[j]-1
		else:
			if ans<hc[i]+wc[j]:
				ans=hc[i]+wc[i]
print(ans)

### FIXED CODE ###

h,w,m=map(int, input().split())
a=[0]*m
hc=[0]*w
wc=[0]*h
for i in range(m):
	x,y=map(int, input().split())
	a[i]=[x-1,y-1]
	hc[y-1]+=1
	wc[x-1]+=1
hcm=max(hc)
wcm=max(wc)
hk=[0]*w
wk=[0]*h
for i in range(len(hc)):
	if hc[i]==hcm:
		hk[i]=1
for i in range(len(wc)):
	if wc[i]==wcm:
		wk[i]=1
c=0
for i in range(len(a)):
	if wk[a[i][0]]==1 and hk[a[i][1]]==1:
		c+=1
if c==sum(hk)*sum(wk):
	print(hcm+wcm-1)		
else:
	print(hcm+wcm)
import sys
import numpy as np
readline=sys.stdin.readline
read=sys.stdin.read

n,c=map(int,readline().split())
m=2*10**5
stc=[list(map(int,l.split())) for l in read().splitlines()]
cht=np.array([])
for e in stc:
  w=e[1]-e[0]
  cht.vstack((cht,np.pad(np.ones(2*(e[1]-e[0])+1),(2*e[0]-1,m-2*e[1]),\
                mode='constant',constant_values=(1,1))))
mnr=0
for i in range(1,m+1):
  mnr=max(mnr,sum(cht[ch][i] for ch in range(c)))
print(mnr)


### FIXED CODE ###

import sys
readline=sys.stdin.readline
read=sys.stdin.read

n,c=map(int,readline().split())
m=2*10**5
stc=[list(map(int,l.split())) for l in read().splitlines()]
cht=[[0]*(m+1) for _ in range(c)]
for e in stc:
  cht[e[2]-1][2*e[0]-1:2*e[1]]=[1 for _ in range(2*e[1]-2*e[0]+1)]
mnr=0
for i in range(1,m+1):
  mnr=max(mnr,sum(cht[ch][i] for ch in range(c)))
print(mnr)
N, M = map(int, input().split())
A = list(map(int, input().split()))

A.sort(reverse=True)

if A[M] < 1/(4*M)*sum(A):
    print("No")
else:
    print("Yes")

### FIXED CODE ###

N, M = map(int, input().split())
A = list(map(int, input().split()))

A.sort(reverse=True)

if A[M-1] < 1/(4*M)*sum(A):
    print("No")
else:
    print("Yes")
a,b,c=map(int,input().split())
print(str(max(c-a+b,0))

### FIXED CODE ###

a,b,c=map(int,input().split())
print(str(max(c-a+b,0)))
A,B = map(int, input().split())
X = int((A/0.08)+0.5)
Y = int((B/0.1)+0.5)
min = 0
if X == Y:
    min = X
elif X > Y:
    if int(X*0.1) == B:
        min = X
    else :
        min = -1
elif X < Y:
    if int(Y*0.08) == A:
        min = Y
    else :
        min = -1

print(min)

### FIXED CODE ###

S = input()
if S == 'AAA' or S == 'BBB':
    print('No')
else :
    print('Yes')
N = int(input())
lst = []
count = 0
st = []

for i in range(N):
  if i==0:
  	in_pu = input()
  	l = list(in_pu)
  	lst.append(list(input()))
    st.append(set(l))
    continue
    
  in_pu = input()
  l = list(in_pu)
  lst.append(list(input()))
  
  if set(l) in st:
    count = count + 1
print(count)


### FIXED CODE ###

N = int(input())

lst = []

for i in range(N):
    lst.append("".join(sorted(list(input()))))


d={}
count = 0

for i in lst:
  if not i in d:
    d[i] = 1
    continue
  else:
    d[i] = d[i] + 1
    count = count + d[i]-1


print(count)
while True:

    ary = input().split()

    if ary[1] = "?" :
        break

    if ary[1] = "+" :
        ans = int(ary[0]) + int(ary[2])

    if ary[1] = "-" :
        ans = int(ary[0]) - int(ary[2])

    if ary[1] = "*" :
        ans = int(ary[0]) * int(ary[2])

    if ary[1] = "/" :
        ans = int(ary[0]) / int(ary[2])

    print(ans)



### FIXED CODE ###

while True:
    a = input()

    if '?' in a :
        break
    
    print(int(eval(a)))
usrInput = input()
splitedInput = (usrInpuy.split( ))
clearFlag = True

for i in range(2):
  if splitedInput[i] > 9:
    clearFlag[i] = False

if clearFlag[0] == True && clearFlag[1] == True:
  print(splitedInput[0] + splitedInput[1])
else:
  print(-1)

### FIXED CODE ###

usrInput = input()
splitedInput = usrInput.split()
clearFlag = []

for i in range(2):
    if int(splitedInput[i]) < 10:
        clearFlag.append(True)
    else:
        clearFlag.append(False)

if bool(clearFlag[0]) == True and bool(clearFlag[1]) == True:
    print(int(splitedInput[0]) * int(splitedInput[1]))
else:
    print(-1)
n,m=map(int,input().split())
r={}
for _ in range(m):
  a,b=map(int,input().split())
  a,b=a-1,b-1
  #print(a,b)
  if a not in r: r[a]=[]
  r[a].append(b)
  if b not in r: r[b]=[]
  r[b].append(a)

ans = {0:0}
steps = [m+1]*n
steps[0]=0
def setroot(i,step):
  newroom = [v for v in r[i] if steps[v]>step]
  #print(i,newroom)
  if len(newroom)>0:
    for v in newroom:ans[v]=i;steps[v]=step
    for v in newroom:setroot(v,step+1)
setroot(0,0)
#print(r)
#print(steps)
if len(ans) < n:
  print('No')
  exit()
print('Yes')
for i in range(1,n):
  print(ans[i]+1)


### FIXED CODE ###

f=lambda:map(int,input().split())
n,m=f()
g=[[] for _ in range(n)]
for _ in range(m):
  a,b=f()
  g[a-1]+=[b-1]
  g[b-1]+=[a-1]
p=[0]*n
from collections import*
q=deque([0])
while q:
  v=q.popleft()
  for c in g[v]:
    if p[c]<1: p[c]=v+1; q.append(c)
if 0 in p: print('No')
else: print('Yes',*p[1:],sep='\n')
a=list(map(int,input().split()))
b=list(map(int,input().split()))
no=0
for i in range(0,a[0]):
    if b[i]<=a[1]:
        no+=1 
print(no)        

### FIXED CODE ###

a=list(map(int,input().split()))
if a[0]<a[1]:
    print('0')
else:
    print('10')
a = input()
num = a.split(' ')
N = num[0]
K = num[1]
j = N % K

if j == 0:
	print(0)
else:
	print(1)


### FIXED CODE ###

a = input()
num = a.split(' ')
N = int(num[0])
K = int(num[1])
j = N % K
if j == 0:
	print(0)
else:
	print(1)
from math import gcd
 
a,b=map(int, input().split())
c=input()
d=input()
 
e=gcd(n,m)
 
ae=a//e
be=b//e
 
for i in range(0,e):
    if c[ae*i]!=d[be*i]:
        print(-1)
        exit()
print(ae*be*e)

### FIXED CODE ###

from math import gcd
 
n,m=map(int, input().split())
s=input()
t=input()
 
g=gcd(n,m)
 
ng=n//g
mg=m//g
 
for i in range(0,g):
    if s[ng*i]!=t[mg*i]:
        print(-1)
        exit()
print(ng*mg*g)
n=int(input())
s=[input() for i in range(n)]

d={}

for i in s:
  if i in d:
    d[i]+=1
  else:
    d[i]=1
d=sorted(d.items(),reverse=True)



for i in d.key():
  print(i)


### FIXED CODE ###

#C
#入力
N=int(input())
S=[input() for i in range(N)]

#処理
result={}
for i in S:
    if i in result:
        result[i]+=1
    else:
        result[i]=1

x=max(result.values())

Z=[]
for i in result.items():
    if i[1]==x:
        Z.append(i[0])
Z.sort()
for i in Z:
    print(i)
a = input()
print("%d", a*a*a)


### FIXED CODE ###

a = int(input())
a = a*a*a
print(a)
A,B = [int(x) for x in input().split()]
K = 50
h,w = 2*K,2*K
cntA = A-1
cntB = B-1
print(h,w)
for i in range(h):
    if(i<K):
        pr = ['#'*w]
        for j in range(w):
            if(cntA>0):
                if(i%2==0 and w%2==0):
                    pr[j] = '.'
                    cntA -= 1
                elif(i%2==1 and w%2==1):
                    pr[j] = '.'
                    cntA -= 1
    else:
        pr = ['.'*w]
        for j in range(w):
            if(cntB>0):
                if(i%2==0 and w%2==0):
                    pr[j] = '#'
                    cntA -= 1
                elif(i%2==1 and w%2==1):
                    pr[j] = '#'
                    cntA -= 1
    print(str(*pr))
        

### FIXED CODE ###

A,B = [int(x) for x in input().split()]
K = 50
h,w = 2*K,2*K
cntA = A-1
cntB = B-1
print(h,w)
for i in range(h):
    pr = ''
    if(i<K):
        for j in range(w):
            if(cntA>0):
                if((i%2==0 and j%2==0)):
                    pr += '.'
                    cntA -= 1
                else:
                    pr += '#'
            else:
                pr += '#'
    else:
        pr = ''
        for j in range(w):
            if(cntB>0 and i>K):
                if((i%2==0 and j%2==0)):
                    pr += '#'
                    cntB -= 1
                else:
                    pr += '.'
            else:
                pr += '.'
    print(pr)
N,M,X,Y=map(int,input().split())
x=list(map(int,input().split()))
y=list(map(int,input().split()))
x.sort(reverse=True)
y.sort()
a=0
for z in range(X+1,Y+1):
    if z>x[0] and z<=y[0]:
        a=1
        break
if a=1:
    print('No War')
else:
    print('War')


### FIXED CODE ###

N,M,X,Y=map(int,input().split())
x=list(map(int,input().split()))
y=list(map(int,input().split()))
x.sort(reverse=True)
y.sort()
a=0
for z in range(X+1,Y+1):
    if z>x[0] and z<=y[0]:
        a=1
        break
if a==1:
    print('No War')
else:
    print('War')
n, m = map(int, input().split())
li_X = list(map(int, input().split()))

if(m==1):
    print(0)

else:
    li_X.sort()

    li_X_delta = []
    for i in range(len(li_X)-1):
        li_X_delta.append(li_X[i+1]-li_X[i])

    li_X_delta_sorted_rev = sorted(li_X_delta, reverse=True)
    path_ignorable = []
    cnt = 0

    for i in range(n-1):
        path_ignorable.append(li_X_delta.index(li_X_delta_sorted_rev[cnt]))
        cnt += 1
    # ignore path from li_X[i] to li_X[i+1] for i in path_ignorable
    
    ans = 0
    """
    for i in path_ignorable:
        print("from " + str(i) + " to " + str(i+1))
    """
    for i in range(len(li_X_delta)):
        if(i in path_ignorable):
            continue
        ans += li_X_delta[i]
    print(ans)

### FIXED CODE ###

n, m = map(int, input().split())
li_X = list(map(int, input().split()))

li_X.sort()
li_X_delta = []
for i in range(len(li_X)-1):
    li_X_delta.append(li_X[i+1]-li_X[i])
li_X_delta.sort(reverse=True)
cnt = 0

ans = li_X[-1] - li_X[0]
for i in range(min(n-1, len(li_X_delta))):
    ans -= li_X_delta[i]
print(ans)
i = 0
while True:
    i, n = input(), i+1
    if n == 0:
        break
    print 'Case %d: %d' % (i+1, n)

### FIXED CODE ###

i = 0
while True:
    i, n = i+1, input()               
    if n == 0:
        break
    print 'Case %d: %d' % (i, n)
def main(): 
  MOD = 10e9+7
  n = int(input())
  a = sorted(map(int, input().split()))
  ans = 2**(n//2)
  if n%2:
    if a.pop(0)!=0:ans=0
  i = n%2 - 1
  for j in range(n//2):
    i += 2
    if a[j*2]!=i or a[j*2+1]!=i: ans=0
  print(int(ans%MOD))

if __name__=="__main__":main()

### FIXED CODE ###

n=int(input())
a=sorted(map(int, input().split()))
if n%2: b = [i if not(i%2) else i+1 for i in range(n)]
else: b = [i if i%2 else i+1 for i in range(n)]
if a==b:print((2**(n//2))%(10**9+7))
else: print(0)