Buggy python submission (verdict: Time Limit Exceeded):
#import math
#import copy
#import sys
#import bisect
#input = sys.stdin.readline
mod=10**9+7
def swap(a,b):
    c=a
    a=b
    b=c
    return a,b
def factorial(x): #階乗計算
    n=1
    for i in range(x):
        n=(n*(i+1))%mod
    return n

def gcd(a, b):
    if b == 0:
        return a
    else:
        return gcd(b, a%b)
def lcm(a, b):
    return((a*b)//gcd(a,b))
def div(x): #約数配列
    div=[1]
    check=2
    while(x!=1 and check <= int(x**0.5)+2):
        if(x%check==0):
            div.append(check)
            while(x%check==0):
                x=x//check
        check+=1
    if x != 1:
      div.append(x)
    return div
def div2(x): #素因数分解配列
    div2=[]
    check=2
    while(x!=1 and check <= int(x**0.5)+2):
        while x%check==0:
            div2.append(check)
            x/=check
        check+=1
    if x != 1:
      div2.append(x)
    return div2

def main():
    # x,y = map(int,input().split())           x=1,y=2
    # a = input().split()                      a=['1','2','3',...,'n']
    # a = list(map(int,input().split()))       a=[1,2,3,4,5,...,n]
    # li = input().split('T')	              FFFTFTTFF => li=['FFF', 'F', '', 'FF']
    # 複数行の「1 2 3 4」型の入力を一配列に
    # x = sorted([list(map(int, input().split())) for _ in range(n)])
    # ソート x.sort(key=lambda y:y[1])
    # [chr(i) for i in range(97, 97+26)] 英語小文字リスト
    # [chr(i) for i in range(65, 65+26)] 英語大文字リスト atcoder
    # ord(c) chr(2) alphabet <=> number
    n,k = map(int,input().split()) 
    a = list(map(int,input().split()))
    x=a[0]
    for i in range(n-1):
        x=gcd(x,a[i+1])
    if k in a:
        print("POSSIBLE")
        return
    while k<=max(a):
        k+=x
        if k in a:
            print("POSSIBLE")
            return
    print("IMPOSSIBLE")
main()

Fixed submission:
#import math
#import copy
#import sys
#import bisect
#input = sys.stdin.readline
mod=10**9+7
def swap(a,b):
    c=a
    a=b
    b=c
    return a,b
def factorial(x): #階乗計算
    n=1
    for i in range(x):
        n=(n*(i+1))%mod
    return n

def gcd(a, b):
    if b == 0:
        return a
    else:
        return gcd(b, a%b)
def lcm(a, b):
    return((a*b)//gcd(a,b))
def div(x): #約数配列
    div=[1]
    check=2
    while(x!=1 and check <= int(x**0.5)+2):
        if(x%check==0):
            div.append(check)
            while(x%check==0):
                x=x//check
        check+=1
    if x != 1:
      div.append(x)
    return div
def div2(x): #素因数分解配列
    div2=[]
    check=2
    while(x!=1 and check <= int(x**0.5)+2):
        while x%check==0:
            div2.append(check)
            x/=check
        check+=1
    if x != 1:
      div2.append(x)
    return div2

def main():
    # x,y = map(int,input().split())           x=1,y=2
    # a = input().split()                      a=['1','2','3',...,'n']
    # a = list(map(int,input().split()))       a=[1,2,3,4,5,...,n]
    # li = input().split('T')	              FFFTFTTFF => li=['FFF', 'F', '', 'FF']
    # 複数行の「1 2 3 4」型の入力を一配列に
    # x = sorted([list(map(int, input().split())) for _ in range(n)])
    # ソート x.sort(key=lambda y:y[1])
    # [chr(i) for i in range(97, 97+26)] 英語小文字リスト
    # [chr(i) for i in range(65, 65+26)] 英語大文字リスト atcoder
    # ord(c) chr(2) alphabet <=> number
    n,k = map(int,input().split()) 
    a = list(map(int,input().split()))
    x=a[0]
    for i in range(n-1):
        x=gcd(x,a[i+1])
        if x==1:
            break
    if k in a:
        print("POSSIBLE")
        return
    if x==1 and k<=max(a):
        print("POSSIBLE")
        return
    for i in range(n):
        a[i]-=k
        if a[i]<=0:
            a[i]=-1
        if a[i]%x==0:
            print("POSSIBLE")
            return
    print("IMPOSSIBLE")
main()