Harryxun/stf_run huggingface dataset:
s=str(input())
k=int(input())

l=len(s)
chars=set()
sub1=['']*l


for i in range(l-1):
  n=i+1 #length = n
  for j in range(l-i):
    chars.add(s[j:j+n])

print(sorted(chars)[k-1])

### FIXED CODE ###

s=str(input())
k=int(input())

l=len(s)
chars=set()
chars1=set()
sub1=['']*l

for j in range(l):
    chars1.add(s[j])
    min_c=sorted(chars1)[0]

def subset(st,m):
    substring=set()
    if m==0:
        lst=len(st)
    else:
        lst=m
    for i in range(lst):
        n=i+1 #length = n
        for j in range(lst-i):
            substring.add(st[j:j+n])
    return substring
    
chars=chars|subset(s[max(l-10,0):],0)
for i in range(l):
    if s[i]==min_c:
        chars=chars|subset(s[i:i+5],0)

#print(min_c,chars)

'''
for i in range(l):
    n=i+1 #length = n
    for j in range(l-i):
        chars.add(s[j:j+n])
        #print('i,j,sub',i,j,s[j:j+n])
'''

print(sorted(chars)[k-1])
a=stdin.readline().rstrip()
s=str(a)
x=s.count("1")
print(x)






### FIXED CODE ###

from sys import stdin
a=stdin.readline().rstrip()
x=a.count("1")
print(x)
N=int(input())
l=list(map(int,input().split()))
l2=sorted([num for num in l if num<0])
l3=sorted([num for num in l if num>=0])
if len(l2)%2==0:
  ans=sum([abs(n) for n in l])

else:
  if abs(l2[-1]) < l3[1]:
    x=l2.pop()
  else:
    x=l3.pop(0)
  ans=sum([abs(n) for n in l2])+sum(l3)-abs(x)
print(ans)

### FIXED CODE ###

N=int(input())
l=list(map(int,input().split()))
l2=sorted([num for num in l if num<0])
l3=sorted([num for num in l if num>=0])
if len(l2)%2==0:
  ans=sum([abs(n) for n in l])

elif l3!=[]:
  if abs(l2[-1]) < l3[0]:
    x=l2.pop()
  else:
    x=l3.pop(0)
  ans=sum([abs(n) for n in l2])+sum(l3)-abs(x)
else:
  x=l2.pop()
  ans=sum([abs(n) for n in l2])-abs(x)
print(ans)
N = int(input())
A = input()
B = input()
C = input()
ans = 0
for i in range(N):
	ans += len(set(A[i],B[i],C[i])) - 1
print(ans)

### FIXED CODE ###

N = int(input())
A = input()
B = input()
C = input()
ans = 0
for i in range(N):
	ans += len(set([A[i],B[i],C[i]])) - 1
print(ans)
N, X = list(map(int, input().split()))

L = list(map(int, input().split()))


now = 0
i = 0
while True:
    if now > X:
        break
    now += L[i]
    i += 1

print(i)

### FIXED CODE ###

N, X = list(map(int, input().split()))

L = list(map(int, input().split()))

count = 0
now = 0
for i in L:
    if now > X:
        break
    now += i
    count += 1
if now <= X:
    count += 1
print(count)
if __name__ == "__main__":
  s = input().split(" ")
  R = int(s[0])
  G = int(s[1])
  B = int(s[2])
  N = int(s[3])
  
  count = 0
  for i in range(R):
    sumR = R * i
      for j in range(G):
        sumG = G * j
        for k in range(B):
          sumB = sumB * k
          if sumR + sumG + sumB == N:
            count += 1
            break
  print(count)

### FIXED CODE ###

import sys

if __name__ == "__main__":
	s = input().split(" ")
	print(int(s[0]) - (int(s[1]) - 1))
inp = map(int, input().split())
if (inp[0] < inp[1]) :
  print 0
else:
  print 10

### FIXED CODE ###

a, b = map(int, input().split())
if a < b :
  print (0)
else:
  print (10)
t=list(raw_input().lower())
c=[0 for i in range(26)]
for i in range(len(t)):
        c[ord(t[i])-ord("a")]+=1
for i in range(26):
        print chr(ord("a")+i),":",c[i]

### FIXED CODE ###

c=[0]*26
while 1:
        try:
                t=list(raw_input().lower())
                for i in range(len(t)):
                        if 0<=ord(t[i])-ord("a")<=25:
                                c[ord(t[i])-ord("a")]+=1
        except EOFError:
                break
for i in range(26):
        print chr(ord("a")+i),":",c[i]
S=input()
c=['Sunny','Cloudy','Rainy','Sunny']
for i,n in enumerate(c[:3]):
  if S==n:
    print(c[i+1])
	break

### FIXED CODE ###

S=input()
c=['Sunny','Cloudy','Rainy','Sunny']
for i,n in enumerate(c[:3]):
    if S==n:
        print(c[i+1])
        break
print (input()**2)

### FIXED CODE ###

print(int(input())**2)
from sys import stdin

N = int(stdin.readline().rstrip())
data = [stdin.readline().rstrip().split() for _ in range(N)]

profit = []
sum_profit = 0

for i in N:
    profit[i] = data[1][i] - data[2][i]
    if profit[i] > 0:
        sum_profit += profit[i]

print(sum_profit)

### FIXED CODE ###

from sys import stdin

N = int(stdin.readline().rstrip())
data = [stdin.readline().rstrip().split() for _ in range(2)]

profit = [0] * N
sum_profit = 0

for i in range(N):
    profit[i] = int(data[0][i]) - int(data[1][i])
    if profit[i] > 0:
        sum_profit += profit[i]

print(sum_profit)
import numpy as np

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

a = np.array(A)
l = int(((N**2)+1)/2)
b = np.tile((1,-1),(1,l))
c = (np.delete(b, 2*l-1, axis=None)).reshape(N,N)
# print(c)
# d = c.reshape(N,N)
print(1)
# inv = 0.5*( np.triu(c) - ( np.tril(c) - np.eye(N) ) )
# g = np.eye(N)
# print(inv)

# x = 2*(np.dot(inv,a))
# print(x)

# ans = list(map(str, list(map(int, list(x)))))
# print(" ".join(ans))

### FIXED CODE ###

import numpy as np
N = int(input())
A = list(map(int, input().split()))
a = np.array(A)
# l = int(((N*N)+1)/2)
b = []
for i in range(N):
    if i%2==0:
        b.append(1)
    else:
        b.append(-1)
c = np.dot(np.array(b),a)
x = [c]
for j in range(1,N):
    x_j = 2*a[j-1] - x[j-1]
    x.append(x_j)
ans = list(map(str, list(map(int, list(x)))))
print(" ".join(ans))
s = int(input())
l = []
for i in range(len(s)-1):
  l.append(s[i:i+2])
print("Yes" if "AC" in l else "No") 

### FIXED CODE ###

s = input()
l = []
for i in range(len(s)-1):
  l.append(s[i:i+2])
print("Yes" if "AC" in l else "No")
#from math import gcd
from fractions import gcd
from functools import reduce
import numpy as np
import sys
#import time

"""
def input():
    return sys.stdin.readline()[:-1]
"""

def lcm(a, b):
	return a * b // gcd(a, b)

def main():
	mod = 10**9 + 7
	N = int(input())
	A = list(map(int, input().split()))

	ans = reduce(lcm, A)
	"""
	a = 1
	for i in A:
		a = lcm(a, i)
	"""
	#print(a, ans)
	B = np.array([ans//i for i in A])
	print(np.sum(B) % mod)

if __name__ == "__main__":
	main()


### FIXED CODE ###

#from math import gcd
from fractions import gcd
from functools import reduce

mod = 10**9 + 7

def lcm(a, b):
	return a * b // gcd(a, b)


N = int(input())
A = [i for i in map(int, input().split())]

ans = reduce(lcm, A)

#print(ans)
B = [ans//i for i in A]

print(sum(B) % mod)
import sys
import os
import math

def make_divisors(n):
    divisors = []
    for i in range(1, int(n**0.5)+1):
        if n % i == 0:
            divisors.append(i)
            if i != n // i:
                divisors.append(n//i)

    # divisors.sort()
    return divisors

N = int(input())
listN = make_divisors(N)
mini = 10**12
if len(listN) == 1:
    x = N
    y = 1
else:
    for i in range(0,len(listN),2):
        x = listN[i]
        y = listN[i+1]
        mini = min(x+y,mini)
print(x-1+y-1)


### FIXED CODE ###

import sys
import os

def make_divisors(n):
    divisors = []
    for i in range(1, int(n**0.5)+1):
        if n % i == 0:
            divisors.append(i)
            if i != n // i:
                divisors.append(n//i)

    # divisors.sort()
    return divisors

N = int(input())
listN = make_divisors(N)
mini = 10**12
if len(listN) == 1:
    x = N
    y = 1
else:
    for i in range(len(listN)):
        x = listN[i]
        y = N//x
        mini = min(x+y,mini)
print(x-1+y-1)
2
6 8
3 3

### FIXED CODE ###

n =int(input())

total = 0
for i in range(n):
    a = list(map(int, input().split()))
    total += a[1] - a[0] + 1

print(total)
import sys
input = sys.stdin.reaedline

def main():
	x = int(input())

	if x >= 30:
      print("Yes")
    else:
      print("No")
main()

### FIXED CODE ###

def main():
    x = int(input())
 
    if x >= 30:
        print("Yes")
    else:
        print("No")
main()
days = int(input())
assi = int(input())
lst = []
while(assi > 0):
    a = int(input())
    assi -= 1
    lst.append(a)
    tot = sum(lst)
if (days > tot):
    print(days-tot)
elif (days == tot):
    print(days-tot)
else:
    print('-1')

### FIXED CODE ###

days , assi = map(int,input().split())
lst = []
lst = [int(i) for i in input().split()]
tot = sum(lst)
if (tot>days):
    print(-1)
else:
    print(days-tot)
while(1):
  a,b = map(int, raw_input().split())
  op = f.read()

  if op == "+":
    print "%d" %(a+b)
  elif op == "-":
    print "%d" %(a-b)
  elif op == "*":
    print "%d" %(a*b)
  elif op == "/":
    print "%d" %(a/b)
  elif op == "?":
    break

### FIXED CODE ###

while(1):
  a,op,b = raw_input().split()
  a = int(a)
  b = int(b)
  if op == "+":
    print (a+b)
  elif op == "-":
    print (a-b)
  elif op == "*":
    print (a*b)
  elif op == "/":
    print (a/b)
  elif op == "?":
    break
def main():
    import sys
    input = sys.stdin.readline
    from bisect import bisect_left, bisect_right

    N, M = map(int, input().split())
    AB = []
    for i in [0]*N:
        A, B = map(int, input().split())
        AB.append((A, B))
    AB.sort(key=lambda x:x[0])

    POWER = 1
    x = [0] * (N+1)
    x[0] = AB[0][POWER]
    for i in range(N-1):
        x[i+1] = AB[i][POWER] ^ AB[i+1][POWER]
    x[N] = AB[N-1][POWER]

    graph = [ [] for _ in [0]*(N+2) ]
    for i in range(1, M+1):
        L, R = map(int, input().split())
        L = bisect_left(AB, (L, 0))
        R = bisect_right(AB, (R, 1))
        graph[L].append((R, i))
        graph[R].append((L, i))

    ans = []
    POS = 0
    ID = 1
    def dfs(v):
        used[v] = True
        res = x[v]
        for edge in graph[v]:
            if used[edge[POS]]: continue
            r = dfs(edge[POS])
            if r: ans.append(edge[ID])
            res ^= r
        return res

    used = [False] * (N+1)
    for i in range(N+1):
        if used[i]: continue
        if dfs(i):
            print(-1)
            return

    print(len(ans))
    ans.sort()
    print(*ans)


main()

### FIXED CODE ###

def main():
    import sys
    input = sys.stdin.readline
    from bisect import bisect_left, bisect_right
    sys.setrecursionlimit(10**9)

    N, M = map(int, input().split())
    AB = []
    for i in [0]*N:
        A, B = map(int, input().split())
        AB.append((A, B))
    AB.sort(key=lambda x:x[0])

    POWER = 1
    x = [0] * (N+1)
    x[0] = AB[0][POWER]
    for i in range(N-1):
        x[i+1] = AB[i][POWER] ^ AB[i+1][POWER]
    x[N] = AB[N-1][POWER]

    graph = [ [] for _ in [0]*(N+1) ]
    for i in range(1, M+1):
        L, R = map(int, input().split())
        L = bisect_left(AB, (L, 0))
        R = bisect_right(AB, (R, 1))
        graph[L].append((R, i))
        graph[R].append((L, i))

    ans = []
    POS = 0
    ID = 1
    def dfs(v):
        used[v] = True
        res = x[v]
        for edge in graph[v]:
            if used[edge[POS]]: continue
            r = dfs(edge[POS])
            if r: ans.append(edge[ID])
            res ^= r
        return res

    used = [False] * (N+1)
    for i in range(N+1):
        if used[i]: continue
        if dfs(i):
            print(-1)
            return

    print(len(ans))
    ans.sort()
    print(*ans)


main()
s=int(input())
n=len(s)//2
while n!=0:
  
  if s[:n]==s[n:2*n]:
    print(n)
    break
  n=-1

### FIXED CODE ###

s=input()
n=len(s)//2
n-=1
while n!=0:
  if s[:n]==s[n:2*n]:
    print(2*n)
    break
  n-=1
x=int(input())

for b in range(0,200):
  b5 = b**5
  a5 = x + b5
  a = int( float(a5)**0.2 )
  if a**5 == a5:
    print(a,b)
    break
  a5 = x - b5
  a = int( float(a5)**0.2 )
  if a**5 == a5:
    print(a,-b)
    break
#


### FIXED CODE ###

x=int(input())

for a in range(0,200):
  a5 = a**5
  b5 = a5 - x
  if b5 >= 0:
    b = int( float(b5)**0.2 )
    if b**5 == b5:
      print(a,b)
      break
  else:
    b5 = -b5
    b = int( float(b5)**0.2 )
    if b**5 == b5:
      print(a,-b)
      break
#
n,a=map(int,input().split())
print("Yes" if (n%500) <= a else "No")



### FIXED CODE ###

n=int(input())
a=int(input())
print("Yes" if (n%500) <= a else "No")
sum=26
count=0
n = int(input())
k = ord('a')-1
while(sum<n) :
  count+=1
  sum+=26**(count+1)

current=n
mozi=''
mozi1=''
for i in range(count+1) :
  mozi+='z'
if current==sum :
  print(mozi)
else :
  for i in reversed(range(count+1)) :
    c=current//26**i
    
    mozi1+=chr(c+k)
    current = current % 26 ** i
  print(mozi1)

### FIXED CODE ###

n,k = map(int, input().split())
a_list=list(map(int, input().split()))
a_list=sorted(a_list)
print(sum(a_list[:k]))
n, k = map(int, input().split())
a = [int(i) for i in input().split()]

lst = []
visit_now = 1
visit_list = [0] * n

while True:
    if visit_list[visit_now - 1] == 1:
        break
    visit_list[visit_now - 1] = 1
    lst.append(visit_now)
    visit_now = a[visit_now - 1]


start = lst.index(visit_now)
loop_num = n - start - 1

if k <= start:
    ans = lst[k]
else:
    k -= start
    k %= loop_num
    ans = lst[start + k]

print(ans)

### FIXED CODE ###

n, k = map(int, input().split())
a = [int(i) for i in input().split()]


lst = []
visit_now = 1
visit_list = [-1] * (n + 1)
cnt = 0

while visit_list[visit_now - 1] == -1:
    visit_list[visit_now - 1] = cnt
    lst.append(visit_now)
    visit_now = a[visit_now - 1]
    cnt += 1

start = visit_list[visit_now - 1]
loop_num = cnt - start

if k <= start:
    ans = lst[k]
else:
    k -= start
    k %= loop_num
    ans = lst[start + k]

print(ans)
from math import factorial

n,k = map(int,input().split())
mod = 10**9+7

def comb(n,r):
    return factorial(n) / (factorial(r) * factorial(n-r))

for i in range(1,k+1):
    x = comb(k-1,k-i) % mod
    if n-k+1 >= i:
        y = comb(n-k+1,i) % mod
    elif i > n-k+1:
        y = 0
    print(int(x*y)%mod)

### FIXED CODE ###

from math import factorial

n,k = map(int,input().split())
mod = 10**9+7

def cmb(n,r):
    return factorial(n) // (factorial(r) * factorial(n-r))

for i in range(1,k+1):
    if n-k+1 < i or k-1 < i-1:
        print(0)
    else:
        x = cmb(k-1,i-1) % mod
        y = cmb(n-k+1,i) % mod
        ans = (x*y) % mod
        print(int(ans))
import sys
stdin = sys.stdin
 
sys.setrecursionlimit(10**5) 
 
def li(): return map(int, stdin.readline().split())
def li_(): return map(lambda x: int(x)-1, stdin.readline().split())
def lf(): return map(float, stdin.readline().split())
def ls(): return stdin.readline().split()
def ns(): return stdin.readline().rstrip()
def lc(): return list(ns())
def ni(): return int(stdin.readline())
def nf(): return float(stdin.readline())

from collections import deque

def bfs(grid: list):
    h = len(grid)
    w = len(grid[0])
    
    dhs = [0, 1, 0, -1]
    dws = [1, 0, -1, 0]
    
    que = deque([(1,(0,0))])
    grid[0][0] = "1"
    
    while que:
        cost, (hcur, wcur) = que.popleft()
    
        for dh, dw in zip(dhs, dws):
            if 0 <= hcur+dh < h and 0 <= wcur+dw < w and grid[hcur+dh][wcur+dw] == ".":
                nex_cost = cost + 1
                grid[hcur+dh][wcur+dw] = str(nex_cost)
                que.append((nex_cost, (hcur+dh, wcur+dw)))
    

h,w = li()

grid = []
for _ in range(h):
    grid.append(lc())

whites = 0
for row in grid:
    whites += row.count(".")

bfs(grid)

print(whites - int(grid[-1][-1]))

### FIXED CODE ###

from collections import deque

H, W = map(int, input().split())

inp = []
for h in range(H):
    inp.append(input())

field = []
field.append(["#" for _ in range(W+2)])
for h in range(H):
    field.append(["#"] + list(inp[h]) + ["#"])    
field.append(["#" for _ in range(W+2)])


def bfs():
    que = deque([])
    next_h = [1,0,-1, 0]
    next_w = [0,1, 0,-1]
    
    que.append([0,1,1])
    
    while len(que) != 0:
        dist,h,w = que.popleft()
        if field[h][w] != ".":
            continue
        
        field[h][w] = str(dist)
        
        for i in range(4):
            if field[h+next_h[i]][w+next_w[i]] == ".":
                que.append([dist+1, h+next_h[i], w+next_w[i]])
            
    return field[H][W]
    

points = 0
for field_row in field:
    for point in field_row:
        if point == ".":
            points += 1


min_dist = bfs()

if min_dist == '.':
    print(-1)
else:
    print(points - int(min_dist) - 1)
n = int(input())
a = list(map(int, input().split()))
a.sort()
flag = [True] * (a[-1]*2)
for i, num in enumerate(a):
    if a[(i-1)%n]==num or a[(i+1)%n]==num:
        flag[num] = False
        continue
    for j in range(2, a[-1]//num+2):
        flag[j*num] = False
counter = 0
for i in a:
    if flag[i]:
        counter += 1
print(counter)

### FIXED CODE ###

n = int(input())
a = list(map(int, input().split()))
a.sort()
flag = [True] * (a[-1]*3)
for i, num in enumerate(a):
    if a[(i-1)%n]==num or a[(i+1)%n]==num:
        if i-1>=0 or i+1<n:
            flag[num] = False
    for j in range(2, a[-1]//num+2):
        flag[j*num] = False
counter = 0
for i in a:
    if flag[i]:
        counter += 1
print(counter)
from operator import mul
from functools import reduce

N, K=map(int, input().split())
red=N-K

def cmb(n, r):
  if(n<r):
    return 0
  r=min(r,n-r)
  if(r==0):
      return 1
  
  
  upper=reduce(mul, range(n, n-r, -1))
  under=reduce(mul, range(1,r+1))
    
  return upper / under


for i in range(1,K+1):
  ret = cmb(N-K+1,i)*cmb(K-1,i-1)
  print(ret%(1e9+7))

### FIXED CODE ###

from operator import mul
from functools import reduce


def cmb(n, r):
	if n < r:
		return 0
	r = min(n - r, r)
	if r == 0:
		return 1
	numer = reduce(mul, range(n, n - r, -1))
	denom = reduce(mul, range(1, r + 1))
	return numer // denom % INF


N, K = map(int, input().split())
INF = 10 ** 9 + 7

for i in range(1, K + 1):
	print(cmb(K - 1, i - 1) * cmb(N - K + 1, i) % INF)
n=int(input())
l=[int(i) for i in input().split()]
from collections import Counter 
c=Counter(l)
arr=[i for i in c if c[i]>=2]
arr.sort(reverse=1)
if len(arr)==1 and c[arr[0]]>=4:
    print(0)
else:
    print(arr[0]*arr[1])

### FIXED CODE ###

n=int(raw_input())
l=[int(i) for i in raw_input().split()]
from collections import Counter 
c=Counter(l) 
ans=[]
for i in c: 
    if c[i]>=2:
        ans=ans+[i]*(c[i]//2)
ans.sort(reverse=1)
if len(ans)<=1:
    print(0)
else: 
    print(ans[0]*ans[1])
N, K = map(int, input().split())
H = list(map(int, input().split()))

H.sort(reverse=True)

if K >= N:
    print(0)
else:
    for i in range(K):
        del H[i]
    print(sum(H))


### FIXED CODE ###

N, K = map(int, input().split())
H = list(map(int, input().split()))

H.sort(reverse=True)

if K >= N:
    print(0)
else:
    print(sum(H[K:]))
N,M=map(int,input().split())
unionfindTree = [i for i in range(N)]
size = [1 for _ in range(N)]
inconvenience = N*(N-1)//2
answers = [inconvenience] #M bridges destroyed
#answers[i] should be inconvenience after M-i bridges destroyed.

def root(x):
    p = unionfindTree[x]
    if x==p:
        return(p)
    else:
        unionfindTree[x] = root(p)
        # size[x] = size[p]
        return(unionfindTree[x])

def getsize(x):
    r = root(x)
    return(size[r])

def union(x,y):
    rx = root(x)
    ry = root(y)
    convenience = 0
    if rx != ry:
        unionfindTree[ry] = rx
        sx = size[rx]
        sy = size[ry]
        convenience = sx * sy
        size[rx] = sx+sy
    return(convenience)

revBridges = []
for _ in range(M):
    a,b = map(int,input().split())
    revBridges.append((a-1,b-1))
revBridges.reverse()

for i in range(M):
    a,b = revBridges[i]
    c = union(a,b)
    inconvenience -= c
    answers.append(inconvenience)
    # print("link",(a,b))
    # print(unionfindTree)
    # print([getsize(i) for i in range(N)])

for i in range(M):
    print(answers[M-1-i])

### FIXED CODE ###

N,M = map(int,input().split())
edges = []
for _ in range(M):
    a,b = map(int,input().split())
    edges.append((a-1,b-1))
edges.reverse()
parents = list(range(N))
size = [1 for _ in range(N)]
rank = [0 for _ in range(N)]

def root(x):
    px = parents[x]
    if px == x:
        return(x)
    else:
        r = root(px)
        parents[x] = r
        return(r)

def same(x,y):
    return(root(x) == root(y))

def union(x,y):
    rx = root(x)
    ry = root(y)
    if rx == ry:
        return(0)
    if rank[ry] > rank[rx]:
        parents[rx] = ry
        size[ry] += size[rx]
    else:
        parents[ry] = rx
        size[rx] += size[ry]
        if rank[rx] == rank[ry]:
            rank[rx] += 1
    return(1)

inconvinience = N*(N-1)//2
answers=[inconvinience]

for edge in edges:
    x,y = edge
    rx = root(x)
    ry = root(y)
    sx = size[rx]
    sy = size[ry]
    res = union(rx,ry)
    if res == 1:
        inconvinience -= sx*sy
    answers.append(inconvinience)

answers.reverse()

for answer in answers[1:]:
    print(answer)
while 1:
 i=1
 j=int(input)
 if j==0:
  break
 print("Case",str(i)+":",j)
 i+=1

### FIXED CODE ###

i=1
while 1:
 j=int(input())
 if j==0:
  break
 print("Case",str(i)+":",j)
 i+=1
N = int(input())
arr = sorted([int(i) for i in input().split()])
ok = True
b = {}
for i in range(N):
    if arr[i] not in b:
        b[arr[i]] = 1
    else:
        b[arr[i]] += 1
if N%2 :
    if b[0] != 1:
        ok = False
    for i in range(1,(N-1)//2+1):
        if ok== False:
            break
        if b[2*i]!= 2:
            ok = False
else:
    for i in range(1,N//2+1):
        if b[2*i-1] != 2:
            ok = False

if ok :
    print(2**(N//2)%(10**9+7))
else:
    print(0)

### FIXED CODE ###

N = int(input())
arr = sorted([int(i) for i in input().split()])
ok = True
b = {}
for i in range(N):
    if arr[i] not in b:
        b[arr[i]] = 1
    else:
        b[arr[i]] += 1
if N%2 :
    if b[0] != 1:
        ok = False
    for i in range(1,(N-1)//2+1):
        if ok== False:
            break
        if 2*i not in b or b[2*i]!= 2:
            ok = False
else:
    for i in range(1,N//2+1):
        if 2*i-1 not in b or b[2*i-1] != 2:
            ok = False
            break

if ok :
    print(2**(N//2)%(10**9+7))
else:
    print(0)
#  --*-coding:utf-8-*--


import math

def f(a, b, c):
    return b//c - (a-1)//c


def main():
    A,B,C,D = map(int, input().split())
    
    x = B - A + 1 - f(A,B,C) - f(A, B, D) + f(A, B, C*D//math.gcd(C, D))
    print(x)





if __name__ == '__main__':
    main()


### FIXED CODE ###

#  --*-coding:utf-8-*--


def gcd(n, m):
    while(m > 0):
        n,m = m, n%m
    
    return n


def f(a, b, c):
    return b//c - (a-1)//c


def main():
    A,B,C,D = map(int, input().split())
    
    x = B - A + 1 - f(A,B,C) - f(A, B, D) + f(A, B, C*D//gcd(C, D))
    print(x)





if __name__ == '__main__':
    main()
r=lambda x:p[x]>=0and r(p[x])or x
(n,m,k),*t=[map(int,t.split())for t in open(0)]
p,f=[-1]*-~n,[-1]*-~n
for a,b in t[:m]:
  x,y=r(a),r(b)
  if x!=y:
    if x>y:x,y=y,x
    p[x]+=p[y]
    p[y]=x
  f[a]-=1,
  f[b]-=1,
a=[f[i]-p[r(i)]for i in range(n+1)]
for c,d in t[m:]:
  if r(c)==r(d):
    a[c]-=1
    a[d]-=1
print(*a[1:])

### FIXED CODE ###

def root(x):
  while par[x]>=0:x=par[x]
  return x
def unite(x,y):
  x,y=root(x),root(y)
  if x!=y:
    if x>y:x,y=y,x
    par[x]+=par[y]
    par[y]=x
def same(x,y):
  return root(x)==root(y)
def size(x):
  return-par[root(x)]
n,m,k,*t=map(int,open(0).read().split())
par=[-1]*n
f=[set()for _ in range(n)]
for a,b in zip(*[iter(t[:m*2])]*2):
  a-=1
  b-=1
  unite(a,b)
  f[a].add(b)
  f[b].add(a)
a=[size(i)-len(f[i])-1for i in range(n)]
for c,d in zip(*[iter(t[m*2:])]*2):
  c-=1
  d-=1
  if same(c,d):
    a[c]-=1
    a[d]-=1
print(*a)
a=input()
i=0
while i<a:
    if a[i]='?':
        print(end='D')

    else:
        print(end=str(a[i]))

### FIXED CODE ###

a=input()
i=0
while i<len(a):
    if a[i]=='?':
        print(end='D')

    else:
        print(end=str(a[i]))
    i=i+1
N = input()
a = [input() for i in range(N)]
print (a.reverse())

### FIXED CODE ###

n = int(input())
print(" ".join(input().split()[::-1]))
from math import sqrt

a, b, c = map(int, input().split())

if sqrt(a)+sqrt(b)-sqrt(c) < 0:
    print('Yes')
else:
    print('No'

### FIXED CODE ###

a, b, c = map(int, input().split())

if c-(a+b) >= 0:
    if 4*a*b < (c-(a+b))**2:
        print('Yes')
    else:
        print('No')
else:
        print('No')
l,r = map(int,input().split())

if r-l >= 2019:
      print(0)
else:
      m = 2019
      for i in range(l,r):
            for j in range(i+1,r+1):
                  m = min(m,(i*j)%2019)
print(m)


### FIXED CODE ###

from itertools import combinations

l,r = map(int,input().split())

if r - l >= 2019:
    print(0)
else:
    m = 2019
    for i, j in combinations(range(l, r+1),2):
        tmp = i*j % 2019
        if m > tmp:
            m = tmp
    print(m)