Harryxun/sft_time huggingface dataset:
### BUGGY CODE ###

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

def func(n):
    if n == 1:
        return [1, 3, 1]
    else:
        temp=func(n-1)
        return  [temp[0] + 1] + temp[1:] + [1] +\
                temp[:-1] + [temp[-1] + 1]

bg = func(N)
#print(bg)
cumulative = [0]
for i in range(len(bg)):
    cumulative.append(cumulative[i] + bg[i])
#print(cumulative)

#do binary search
left, right = -1, len(bg)

while right - left > 1:
    mid = (left + right) // 2
    if cumulative[mid] < X:
        left = mid
    else:
        right = mid


#print(right)
if right % 2 == 1: #in B
    print(sum([bg[i] for i in range(1, right, 2)]))
else:
    print(X - sum([bg[i] for i in range(0, right, 2)]))


### FIXED CODE ###

N, X = map(int, input().split())
a = [1]
for _ in range(N - 1):
    a.append(a[-1] * 2 + 3)
p = [1]
for _ in range(N - 1):
    p.append(p[-1] * 2 + 1)
# print(a)
# print(p)
def func(n, x):
    if n == 0 and x == 1:
        return 1
    if x == 1:
        return 0
    elif x <= 1 + a[n - 1]:
        return func(n - 1, x - 1)
    elif x == 2 + a[n - 1]:
        return p[n - 1] + 1
    elif x <= 2 + a[n - 1] * 2:
        return p[n - 1] + 1 + func(n - 1, x - a[n - 1] - 2)
    else:
        return p[n - 1] * 2 + 1

print(func(N, X))
### BUGGY CODE ###

n = int(input())
a = [list(map(int, input().split())) for _ in range(n)]

MOD = 10**9 +7
dp = [0] * (1<<n)

pair_dic = {}
for i in range(n+1):
    pair_dic[i] = []

for i in range(1<<n):
    pair_dic[ bin(i).count('1') ].append(i)

dp[0] = 1

for i in range(n):
    for k in range(n):
        if(a[i-1][k] == 0):
            continue
        for j in pair_dic[i]:
            if(  ((j&(1<<k)) >>k == 0 ) ):
                dp[j + (1<<k)] += dp[j]
                dp[j + (1<<k)] = dp[j + (1<<k)] % MOD

print(dp[-1])

### FIXED CODE ###

def main():

    n = int(input())
    a = [list(map(int, input().split())) for _ in range(n)]

    MOD = 10**9 +7
    dp = [0] * (1<<n)

    pair_dic = {}
    for i in range(n+1):
        pair_dic[i] = []

    for i in range(1<<n):
        pair_dic[ bin(i).count('1') ].append(i)

    dp[0] = 1

    for i in range(n):
        for k in range(n):
            if(a[i-1][k] == 0):
                continue
            for j in pair_dic[i]:
                if(  ((j&(1<<k)) >>k == 0 ) ):
                    dp[j + (1<<k)] += dp[j]
                    dp[j + (1<<k)] = dp[j + (1<<k)] % MOD

    print(dp[-1])

if __name__ == '__main__':
    main()
### BUGGY CODE ###

from functools import reduce
from operator import mul
import sys

input = sys.stdin.readline

n = int(input())
An = [int(x) for x in input(). split()]

for i in range(n):
    if An[i] == 0:
        print(0)
        quit()

j = 1000000000000000000
ans = 1
ans = reduce(mul, An)


if ans > j :
    print(-1)
    
else :
    print(ans)



### FIXED CODE ###


n = int(input())
An = [int(x) for x in input().split()]
An.sort(reverse=True)

if 0 in An:
    print(0)
    exit()

j = 10 ** 18
ans = 1
for i in range(n):
    if ans > j:
        print(-1)
        quit()
    ans *= An[i]

if ans > j :
    print(-1)
    
else :
    print(ans)
### BUGGY CODE ###

import sys
input=sys.stdin.readline
sys.setrecursionlimit(10**7)
mod=10**9+7
n=int(input())
edges=[[] for _ in range(n)]
for _ in range(n-1):
    x,y=map(int,input().split())
    edges[x-1].append(y-1)
    edges[y-1].append(x-1)
C=[[] for _ in range(n)]

def fill_C(v,par):
    for c in edges[v]:
        if c==par:
            continue
        C[v].append(c)
        fill_C(c,v)
fill_C(0,-1)

DP=[[-1,-1] for _ in range(n)]

def white(v):
    if DP[v][0]!=-1:
        return DP[v][0]
    res=1
    for c in C[v]:
        res*=white(c)+black(c)
        res%=mod
    DP[v][0]=res
    return res
def black(v):
    if DP[v][1]!=-1:
        return DP[v][1]
    res=1
    for c in C[v]:
        res*=white(c)
        res%=mod
    DP[v][1]=res
    return res

print((black(0)+white(0))%mod)

### FIXED CODE ###

import sys
input=sys.stdin.readline
sys.setrecursionlimit(10**7)
mod=10**9+7
n=int(input())
edges=[[] for _ in range(n)]
for _ in range(n-1):
    x,y=map(int,input().split())
    edges[x-1].append(y-1)
    edges[y-1].append(x-1)
root=-1
l=-1
for i in range(n):
    if len(edges[i])>l:
        root=i
        l=len(edges[i])
C=[[] for _ in range(n)]

def fill_C(v,par):
    for c in edges[v]:
        if c==par:
            continue
        C[v].append(c)
        fill_C(c,v)
fill_C(root,-1)

DP=[[-1,-1] for _ in range(n)]

def white(v):
    if DP[v][0]!=-1:
        return DP[v][0]
    res=1
    for c in C[v]:
        res*=white(c)+black(c)
        res%=mod
    DP[v][0]=res
    return res
def black(v):
    if DP[v][1]!=-1:
        return DP[v][1]
    res=1
    for c in C[v]:
        res*=white(c)
        res%=mod
    DP[v][1]=res
    return res

print((black(root)+white(root))%mod)
### BUGGY CODE ###

import sys
def I(): return int(sys.stdin.readline())
def LI(): return list(map(int,sys.stdin.readline().split()))
mod = 10**9 + 7
inf = float('inf')

S = str(input())
N = len(S)
ans = [0]*N
k = int(1)
R = []
L = []
rcount = int(1)
lcount = int(0)
lLocate = []
for i in range(1,N):
    if S[i]==S[i-1]:
        if k == 1:
            rcount +=1
        else:
            lcount +=1
    else:
        if k==1:
            R.append(rcount)
            lLocate.append(i-1)
            lcount = int(1)
        else:
            L.append(lcount)
            rcount = int(1)

        k *= (-1)


L.append(lcount)

#print(R)
#print(L)
#print(lLocate)
j = int(0)
for i in range(N):
    if i in lLocate:
        ans[i] = (R[j]+1)//2 + L[j]//2
        ans[i+1] = R[j]//2 + (L[j]+1)//2
        j +=1

print(' '.join(map(str, ans)))

### FIXED CODE ###

#from collections import deque
import sys
def I(): return int(sys.stdin.readline())
def LI(): return list(map(int,sys.stdin.readline().split()))
mod = 10**9 + 7

S = str(input())
N = len(S)
ans = [0]*N
k = int(1)
R = []
L = []
rcount = int(1)
lcount = int(0)
lLocate = []
for i in range(1,N):
    if S[i]==S[i-1]:
        if k == 1:
            rcount +=1
        else:
            lcount +=1
    else:
        if k==1:
            R.append(rcount)
            lLocate.append(i-1)
            lcount = int(1)
        else:
            L.append(lcount)
            rcount = int(1)

        k *= (-1)


L.append(lcount)

#print(R)
#print(L)
#print(lLocate)
j = int(0)
#for i in range(N):
#    if i in lLocate:
for i in lLocate:
    r = R[j]
    l = L[j]
    ans[i] = (r+1)//2 + l//2
    ans[i+1] = r//2 + (l+1)//2
    j +=1

print(' '.join(map(str, ans)))
### BUGGY CODE ###

n,k = map(int,input().split())
a = list(map(int,input().split()))
b = [0]*n

if(n<k):
    for i in range(n):
        print(n,end=" ")

for j in range(k):
    b = [0]*n
    for i in range(n):
        l = max(0,i-a[i])
        r = min(n-1,a[i]+i)
        b[l] += 1
        if(r+1<n):
            b[r+1] -= 1
    for i in range(1,n):
        b[i] += b[i-1]
    a = b


for i in a:
    print(i,end=" ")


### FIXED CODE ###

from math import log2
n,k = map(int,input().split())
a = list(map(int,input().split()))
b = [0]*n

if(k > 10*log2(n) + 1):
    for i in range(n):
        print(n,end=" ")

else:
    for j in range(k):
        b = [0]*n
        for i in range(n):
            l = max(0,i-a[i])
            r = min(n-1,a[i]+i)
            b[l] += 1
            if(r+1<n):
                b[r+1] -= 1
        for i in range(1,n):
            b[i] += b[i-1]
        a = b


    for i in a:
        print(i,end=" ")
### BUGGY CODE ###

n, q = map(int, input().split())
s = input()

ac = [0] * n
for i in range(n):
    ac[i] = s[:i+1].count("AC")

for j in range(q):
    l, r = map(int, input().split())
    l, r = l-1, r-1
    print(ac[r] - ac[l])

### FIXED CODE ###

import itertools
n, q = map(int, input().split())
s = input()

ac = [0] * n
for i in range(n-1):
    if s[i] == "A":
        if s[i+1] == "C":
            ac[i+1] = 1
i = itertools.accumulate(ac)
ac = list(i)

for j in range(q):
    l, r = map(int, input().split())
    l, r = l-1, r-1
    print(ac[r] - ac[l])
### BUGGY CODE ###

#darker　and darker
from collections import deque
d=deque()
e=deque()
h,w=map(int,input().split())
field=[]
field.append([True for i in range(w+2)])
#visited_node=0
distance=0
for i in range(h):
    s=input()
    a=[]
    a.append(True)
    for j in range(w):
        if s[j]=="#":
            a.append(True)
            d.append((i+1,j+1))
        else:
            a.append(False)
    a.append(True)
    field.append(a)
field.append([True for i in range(w+2)])
while d:
    for some in d:
        index1,index2=some[0],some[1]
        if field[index1-1][index2]==False:
            field[index1-1][index2]=True
            e.append((index1-1,index2))
        if field[index1+1][index2]==False:
            field[index1+1][index2]=True
            e.append((index1+1,index2))
        if field[index1][index2+1]==False:
            field[index1][index2+1]=True
            e.append((index1,index2+1))
        if  field[index1][index2-1]==False:
            field[index1][index2-1]=True
            e.append((index1,index2-1))
    distance+=1
    d=e
    e=deque()
print(distance-1)

### FIXED CODE ###

#darker　and darker
from collections import deque
d=deque()
e=deque()
h,w=map(int,input().split())
field=[0 for i in range(h+2)]
field[0]=[True for i in range(w+2)]
distance=0
for i in range(h):
    s=input()
    a=[False for i in range(w+2)]
    a[0]=True
    for j in range(w):
        if s[j]=="#":
            a[j+1]=True
            d.append((i+1,j+1))
    a[w+1]=True
    field[i+1]=a
field[h+1]=[True for i in range(w+2)]
while d:
    while d:
        some=d.popleft()
        index1,index2=some[0],some[1]
        if field[index1-1][index2]==False:
                field[index1-1][index2]=True
                e.append((index1-1,index2))
        if field[index1+1][index2]==False:
                field[index1+1][index2]=True
                e.append((index1+1,index2))
        if field[index1][index2+1]==False:
                field[index1][index2+1]=True
                e.append((index1,index2+1))
        if  field[index1][index2-1]==False:
                field[index1][index2-1]=True
                e.append((index1,index2-1))
    distance+=1
    d=e
    e=deque()
print(distance-1)
### BUGGY CODE ###

import sys
import os


def main():
    if os.getenv("LOCAL"):
        sys.stdin = open("input.txt", "r")

    N = int(sys.stdin.buffer.readline().rstrip())
    A = list(map(int, sys.stdin.buffer.readline().split()))
    P = set(A)

    obj = {}
    for p in P:
        obj[p] = A.count(p)

    p = 0
    for v in obj.values():
        if v > 1:
            p += v * (v - 1) // 2

    for a in A:
        print(p - (obj[a] - 1))


if __name__ == '__main__':
    main()


### FIXED CODE ###

import sys
import os
import collections

def main():
    if os.getenv("LOCAL"):
        sys.stdin = open("input.txt", "r")

    N = int(sys.stdin.buffer.readline().rstrip())
    A = list(map(int, sys.stdin.buffer.readline().split()))

    obj = collections.Counter(A)

    p = 0
    for v in obj.values():
        if v > 1:
            p += v * (v - 1) // 2

    for a in A:
        print(p - (obj[a] - 1))


if __name__ == '__main__':
    main()
### BUGGY CODE ###

n = int(input())
a = list(map(int, input().split()))

s = [0]*n

for i in range(n):
    s[i] = str(a.index(i+1) + 1)
print(" ".join(s))

### FIXED CODE ###

n = int(input())
a = list(map(int, input().split()))

ans = [0]*n

for i in range(n):
    ans[a[i]-1] = i + 1
print(" ".join(map(str, ans)))
### BUGGY CODE ###

import sys
def input(): return sys.stdin.readline().rstrip()
def main():
    n=int(input())
    s=input()
    R=[]
    G=[]
    B=[]
    for i in range(1,n+1):
        if s[i-1]=='R':R.append(i)
        elif s[i-1]=='G':G.append(i)
        else:B.append(i)
    sum=0
    for r in R:
        for g in G:
            for b in B:
                n_list=[r,g,b]
                n_list.sort()
                if n_list[1]-n_list[0]!=n_list[2]-n_list[1]:
                    sum+=1
    print(sum)

if __name__=='__main__':
    main()

### FIXED CODE ###

import sys
from collections import Counter
def input(): return sys.stdin.readline().rstrip()
def main():
    n=int(input())
    s=input()
    c_s=Counter(s)
    sum_a=0
    for diff in range(1,(n-1)//2+1):
        for i in range(n-2*diff):
            if s[i]!=s[i+diff] and s[i+diff]!=s[i+2*diff] and s[i]!=s[i+2*diff]:
                sum_a+=1
    print(c_s['R']*c_s['G']*c_s['B']-sum_a)

if __name__=='__main__':
    main()
### BUGGY CODE ###

N = int(input())

count = 0
lst = []
while N > 0:
    lst.append(N%10)
    N //= 10 
lst.reverse()
for i in lst:
  count += i

if count % 9 == 0:
  print("Yes")
else:
  print("No")


### FIXED CODE ###

n = int(input())
result = sum(list(map(int, str(n))))
if result % 9 == 0:
  print("Yes")
else:
  print("No")
### BUGGY CODE ###

# #!/usr/bin/env python3
# # -*- coding: utf-8 -*-
from itertools import combinations


def main():
    N = int(input())
    S = [sorted(input()) for _ in range(N)]
    ptn = list(combinations(S, 2))
    result = 0

    for p in ptn:
        result += all([p[0] == p[1]])
    print(result)


if __name__ == "__main__":
    main()


### FIXED CODE ###

# #!/usr/bin/env python3
# # -*- coding: utf-8 -*-
from collections import defaultdict


def main():
    N = int(input())
    dct = defaultdict(int)

    for i in range(N):
        s = input()
        sorted_s = "".join(sorted(s))
        dct[sorted_s] += 1

    ans = 0
    for k, v in dct.items():
        ans += v * (v - 1) // 2
    print(ans)


if __name__ == "__main__":
    main()
### BUGGY CODE ###

n = int(input())
a = list(map(int, input().split()))
a_uni = list(set(a))

a_ol = {}

for i in a_uni:
    a_co = a.count(i)
    if a_co > 1:
        a_ol[i] = a_co


def_count = sum([i * (i - 1) // 2 for i in a_ol.values()])
for k in range(n):
    if a[k] in a_ol:
        print(def_count - (a_ol[a[k]] - 1))
    else:
        print(def_count)



### FIXED CODE ###

from collections import Counter
n = int(input())
a = list(map(int, input().split()))


a_ol = Counter(a)
def_count = 0
for item in a_ol.items():
    a_co = item[1]
    def_count += a_co * (a_co - 1)

def_count //= 2

for k in a:
    print(def_count - a_ol[k] + 1)
### BUGGY CODE ###

n = int(input())
a = list(map(int, input().split()))
b = set(a)
ans = 0
for i in b:
  temp = a.count(i)
  if temp > i:
    ans += temp-i
  elif temp < i:
    ans += temp
print(ans)

### FIXED CODE ###

n = int(input())
a = list(map(int, input().split()))
b = []
c = {}
ans = 0
for i in range(n):
  if a[i] in c:
    c[a[i]] += 1
  else:
    c[a[i]] = 1
    b.append(a[i])
  
for i in range(len(b)):
  temp=c[b[i]]
  temp2=b[i] 
  if temp > temp2:
    ans += temp-temp2
  elif temp < temp2:
    ans += temp
  
  
print(ans)
### BUGGY CODE ###

import sys
input = sys.stdin.readline
n,m = map(int, input().split(" "))
a = list(map(int, input().split(" ")))
a.sort()
bc=[None]*m
for i in range(m):
    bc[i] = list(map(int, input().split(" ")))
bc = sorted(bc, key=lambda x:x[1], reverse=True)
for [b,c] in bc:
    if c < a[0]:
        break
    for i in range(b):
        if c < a[i]:
            break
        a[i] = c
    a.sort()
print(sum(a))

### FIXED CODE ###

import sys
input = sys.stdin.readline
n,m = map(int, input().split(" "))
a = list(map(int, input().split(" ")))
a.sort()
bc=[None]*m
for i in range(m):
    bc[i] = list(map(int, input().split(" ")))
bc.sort(reverse=True, key=lambda x:x[1])
l=[]
for [b,c] in bc:
    l.extend([c]*b)
    if n < len(l):
        break
for i in range(n):
    if len(l) <= i or l[i] <= a[i]:
        break
    a[i] = l[i]
print(sum(a))
### BUGGY CODE ###

#!/usr/bin/env python
# -*- coding: utf-8 -*-

import numpy as np
s = list(map(int, input().split()))
N = s[0]
M = s[1]

def fib(n):
    a, b = 0, 1
    for i in range(n):
        a, b = b, a + b
    return b


broken = np.array([int(input()) for i in range(M)])
broken = np.append(-1,broken)
broken = np.append(broken,N+1)
#  -1段目とN+1段目が壊れていると表記して一貫した計算が可能に

gaps = np.array([])  # 壊れている段の間にある壊れていない段数
for i in range(M+1):
    gaps = np.append(gaps, broken[i+1]-broken[i]-1)

gaps = np.array(gaps, np.int)  # 整数列に変換

fibs = []
for i in range (max(gaps)):
    fibs.append(fib(i))


if 0 in gaps:
    print(0)
else:
    patterns = 1
    for i in range(len(gaps)):
        patterns *= fibs[gaps[i]-1]
    print(patterns % 1000000007)


### FIXED CODE ###

#!/usr/bin/env python
# -*- coding: utf-8 -*-

import numpy as np
s = list(map(int, input().split()))
N = s[0]
M = s[1]
flag = 0
def fib(n):
    a, b = 0, 1
    c = [1]
    for i in range(n):
        a, b = b, a + b
        c.append(b)
    return c


broken = np.array([int(input()) for i in range(M)])
broken = np.append(-1,broken)
broken = np.append(broken,N+1)
#  -1段目とN+1段目が壊れていると表記して一貫した計算が可能に

gaps = np.array([])  # 壊れている段の間にある壊れていない段数
for i in range(M+1):
    gaps = np.append(gaps, broken[i+1]-broken[i]-1)
    if broken[i+1]-broken[i]-1 == 0:
        flag = 1
        break

gaps = np.array(gaps, np.int)  # 整数列に変換



if flag == 1:
    print(0)
else:
    fibs = fib(max(gaps))
    patterns = 1
    for i in range(len(gaps)):
        patterns *= fibs[gaps[i]-1]
    print(patterns % 1000000007)
### BUGGY CODE ###

def main():
  if 'get_ipython' not in globals():  
    # For Subsession
    N = int(input())
    # b = list(map(int, input().split()))
    b = [int(i) for i in input().split()] 
  else:
    # b = [1,2,1]
    # b = [2,2]
    b = [1,1,1,2,2,1,2,3,2]
    N = len(b)
    
  if check(b) != True:
    print(-1)
    
def check(B):
  # if 'get_ipython' in globals(): print(B)
  lenB = len(B)
  if lenB == 0 :
    return True
  #for i in reversed(range(lenB)):
  for i in range(lenB-1,-1,-1):
    if B[i] == i+1:
      if check(B[:i]+B[(i+1):]) == True:
        print(B[i])
        return True
        break
    
main()

### FIXED CODE ###

import sys

def main():
  if 'get_ipython' not in globals():  
    # For Subsession
    N = int(input())
    b = [int(i) for i in input().split()] 
  else:
    # b = [1,2,1]
    # b = [2,2]
    b = [1,1,1,2,2,1,2,3,2]
    N = len(b)

  ans = []
  while True:
    for i in range(N-1,-1,-1):
      if b[i] == i+1:
        ans.append(i+1)
        del b[i]
        N = N -1
        break
      if i == 0:
        print(-1)
        sys.exit()
    if N == 0:
      break

  for i in reversed(ans):
    print(i)
    
main()
### BUGGY CODE ###

# -*- coding: utf-8 -*-
# 標準入力の取得
R, G, B, N = list(map(int, input().split()))

# 求解処理
r_max = N // R
g_max = N // G
result = 0
for r in range(r_max+1):
    n_r = r * R
    for g in range(g_max+1):
        n_rg = n_r + g*G
        if N < n_rg:
            continue
        if (N - n_rg) % B == 0:
            result += 1


# 結果出力
print(result)


### FIXED CODE ###

# -*- coding: utf-8 -*-
# 標準入力の取得
R, G, B, N = list(map(int, input().split()))


def main() -> None:
    # 求解処理
    r_max = N // R
    g_max = N // G
    result = 0
    for r in range(r_max+1):
        n_r = r * R
        for g in range(g_max+1):
            n_rg = n_r + g*G
            if N < n_rg:
                continue
            if (N - n_rg) % B == 0:
                result += 1

    # 結果出力
    print(result)


if __name__ == "__main__":
    main()
### BUGGY CODE ###

import math
n, p = map(int, input().split())
s = input()

def nCr(n, r):
    if n < r:
        return 0
    return math.factorial(n) // (math.factorial(n - r) * math.factorial(r))

ans = 0
if p == 2 or p == 5:
    for i in range(n):
        if int(s[i]) % p == 0:
            ans += i + 1
else:
    # dp = [0] * p
    # dp[0] = 1
    # tmp = 0
    # for i in range(n)[::-1]:
    #     tmp = (int(s[i]) * pow(10, n - i - 1, p) + tmp) % p
    #     ans += dp[tmp]
    #     dp[tmp] += 1
    # print(dp)

    dp = [0] * p
    dp[0] = 1
    tmp = 0
    for i in range(n)[::-1]:
        tmp = (int(s[i:])) % p
        dp[tmp] += 1
    for i in dp:
        ans += nCr(i, 2)

print(ans)

### FIXED CODE ###

from collections import defaultdict
n, p = map(int, input().split())

s = input()
ans = 0
if p == 2 or p == 5:
    for i in range(n):
        if int(s[i]) % p == 0:
            ans += i + 1
else:
    tmp = 0
    d = defaultdict(int)
    d[0] = 1
    for i in range(n)[::-1]:
        tmp += int(s[i]) * pow(10, n - i - 1, p)
        tmp %= p
        ans += d[tmp]
        d[tmp] += 1
print(ans)
### BUGGY CODE ###

def main():
    mod = 10**9+7 #出力の制限
    N = 5001
    g1 = [1, 1] # 元テーブル
    g2 = [1, 1] #逆元テーブル
    inverse = [0, 1] #逆元テーブル計算用テーブル
    
    for i in range( 2, N + 1 ):
        g1.append( ( g1[-1] * i ) % mod )
        inverse.append( ( -inverse[mod % i] * (mod//i) ) % mod )
        g2.append( (g2[-1] * inverse[-1]) % mod )
    
    Pow=[pow(inverse[2],i,mod) for i in range(N+1)]
    
    def func(n):
        if n%2==0:
            return (-g1[n]*g2[n//2]*Pow[n//2])%mod
        else:
            return 0
    
    import sys
    
    sys.setrecursionlimit(10**4)
    input=sys.stdin.buffer.readline
    
    N=int(input())
    edge=[[] for i in range(N)]
    for i in range(N-1):
        x,y=map(int,input().split())
        edge[x-1].append(y-1)
        edge[y-1].append(x-1)


    dp=[[] for i in range(N)]
    sz=[0 for i in range(N)]

    def dfs(v,pv):
        sz[v]=1
        dp[v]=[0]*(sz[v]+1)
        dp[v][1]=1
        for nv in edge[v]:
            if nv!=pv:
                dfs(nv,v)
                merged=[0]*(sz[v]+sz[nv]+1)
                for i in range(sz[v]+1):
                    for j in range(sz[nv]+1):
                        merged[i+j] +=dp[v][i]*dp[nv][j]
                        merged[i+j]%=mod
                sz[v]+=sz[nv]
                dp[v] =merged
        dp[v][0]=(sum(func(k)*dp[v][k] for k in range(1,sz[v]+1)))%mod

    dfs(0,-1)

    print((-dp[0][0])%mod)

if __name__=="__main__":
    main()


### FIXED CODE ###

mod = 10**9+7 #出力の制限
N = 2*10**5
g1 = [1, 1] # 元テーブル
g2 = [1, 1] #逆元テーブル
inverse = [0, 1] #逆元テーブル計算用テーブル

for i in range( 2, N + 1 ):
    g1.append( ( g1[-1] * i ) % mod )
    inverse.append( ( -inverse[mod % i] * (mod//i) ) % mod )
    g2.append( (g2[-1] * inverse[-1]) % mod )

import sys

sys.setrecursionlimit(10**4)

N=int(input())
edge=[[] for i in range(N)]
parent=[0]*N
deg=[1]*N
deg[0]=0
for i in range(N-1):
    x,y=map(int,input().split())
    edge[x-1].append(y-1)
    edge[y-1].append(x-1)


def prv(v,pv):
    for nv in edge[v]:
        if nv!=pv:
            parent[nv]=v
            prv(nv,v)

prv(0,-1)

for i in range(N):
    new=[]
    for v in edge[i]:
        if v!=parent[i]:
            new.append(v)
    edge[i]=new


from collections import deque
ans = list(v for v in range(N) if deg[v]==0)
deq = deque(ans)
used = [0]*N

while deq:
    v = deq.popleft()
    for t in edge[v]:
        deg[t] -= 1
        if deg[t]==0:
            deq.append(t)
            ans.append(t)


dp=[[] for i in range(N)]
sz=[0 for i in range(N)]

for v in ans[::-1]:
    sz[v]=1
    dp[v]=[0]*(sz[v]+1)
    dp[v][1]=1
    for nv in edge[v]:
        merged=[0]*(sz[v]+sz[nv]+1)
        for i in range(sz[v]+1):
            for j in range(sz[nv]+1):
                merged[i+j]=(merged[i+j]+dp[v][i]*dp[nv][j])%mod
        sz[v]+=sz[nv]
        dp[v] =merged
    for k in range(1,sz[v]+1):
        dp[v][0]=(dp[v][0]-(g1[k]*g2[k//2])%mod*((k+1)%2)*dp[v][k])%mod

print((-dp[0][0]*pow(inverse[2],N//2,mod))%mod)
### BUGGY CODE ###

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

results = A[0]
can = True
zero = False
for i in range(N):
    if A[i]==0:
        zero = True
        break

for i in range(N):
    if i==0:
        continue
    results *= A[i]
    if zero:
        continue
    else:
        if results>10**18:
            can = False
            break

if can:
    print(results)
else:
    print(-1)

### FIXED CODE ###

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

results = A[0]
can = True
zero = False
for i in range(N):
    if A[i]==0:
        zero = True
        break

if zero:
    print(0)
else:
    for i in range(N):
        if i==0:
            continue
        results *= A[i]
        if results>10**18:
            can = False
            break

    if can:
        print(results)
    else:
        print(-1)