Buggy python submission (verdict: Time Limit Exceeded):
k = int(input())

def factorization(n):
    arr = []
    temp = n
    for i in range(2, int(-(-n**0.5//1))+1):
        if temp%i==0:
            cnt=0
            while temp%i==0:
                cnt+=1
                temp //= i
            arr.append([i, cnt])

    if temp!=1:
        arr.append([temp, 1])

    if arr==[]:
        arr.append([n, 1])

    return arr

pn=factorization(k)

go =0
keta = len(str(k))
sevens = []

if k % 2 == 0 or k %5 == 0:
    print(-1)
elif str(k)[-1] == "3":
    for i in range(9,10**100000,10):
        if not str(k * i).count('7') == len(str(k*i)):
            continue
        else:
            print(str(k * i).count('7'))
elif str(k)[-1] == "7":
    for i in range(1,10**100000,10):
        if not str(k * i).count('7') == len(str(k*i)):
            continue
        else:
            print(str(k * i).count('7'))
elif str(k)[-1] == "9":
    for i in range(3,10**100000,10):
        if not str(k * i).count('7') == len(str(k*i)):
            continue
        else:
            print(str(k * i).count('7'))
elif str(k)[-1] == "1":
    for i in range(7,10**100000,10):
        if not str(k * i).count('7') == len(str(k*i)):
            continue
        else:
            print(str(k * i).count('7'))



Fixed submission:
k = int(input())

go = 0
keta = len(str(k))

for i  in range(10**1000000):
    if k % 2 ==0:
        print(-1)
        break
    if k % 5==0:
        print(-1)
        break
    else:
        go =(go*10+7) %k
        if go ==0:
            print(i+1)
            break

Buggy python submission (verdict: Runtime Error):
k = int(input())

def factorization(n):
    arr = []
    temp = n
    for i in range(2, int(-(-n**0.5//1))+1):
        if temp%i==0:
            cnt=0
            while temp%i==0:
                cnt+=1
                temp //= i
            arr.append([i, cnt])

    if temp!=1:
        arr.append([temp, 1])

    if arr==[]:
        arr.append([n, 1])

    return arr

pn=factorization(k)

go =0
keta = len(str(k))
sevens = []

if k % 2 == 0 or k %5 == 0:
    print(-1)
    break
elif str(k)[-1] == "3":
    for i in range(9,10**100000,10):
        if not str(k * i).count('7') == len(str(k*i)):
            continue
        else:
            print(str(k * i).count('7'))
elif str(k)[-1] == "7":
    for i in range(1,10**100000,10):
        if not str(k * i).count('7') == len(str(k*i)):
            continue
        else:
            print(str(k * i).count('7'))
elif str(k)[-1] == "9":
    for i in range(3,10**100000,10):
        if not str(k * i).count('7') == len(str(k*i)):
            continue
        else:
            print(str(k * i).count('7'))
elif str(k)[-1] == "1":
    for i in range(7,10**100000,10):
        if not str(k * i).count('7') == len(str(k*i)):
            continue
        else:
            print(str(k * i).count('7'))



Fixed submission:
k = int(input())

go = 0
keta = len(str(k))

for i  in range(10**1000000):
    if k % 2 ==0:
        print(-1)
        break
    if k % 5==0:
        print(-1)
        break
    else:
        go =(go*10+7) %k
        if go ==0:
            print(i+1)
            break

Buggy python submission (verdict: Runtime Error):
k = int(input())

def factorization(n):
    arr = []
    temp = n
    for i in range(2, int(-(-n**0.5//1))+1):
        if temp%i==0:
            cnt=0
            while temp%i==0:
                cnt+=1
                temp //= i
            arr.append([i, cnt])

    if temp!=1:
        arr.append([temp, 1])

    if arr==[]:
        arr.append([n, 1])

    return arr

pn=factorization(k)

go =0
keta = len(str(k))
sevens = []

if k % 2 == 0 or k %5 == 0:
    print(-1)
    break
elif str(k)[-1] == "3":
    for i in range(9,10**100000,10):
        if not str(k * i).count('7') == len(str(k*i))
            continue
        else:
            print(str(k * i).count('7'))
elif str(k)[-1] == "7":
    for i in range(1,10**100000,10):
        if not str(k * i).count('7') == len(str(k*i))
            continue
        else:
            print(str(k * i).count('7'))
elif str(k)[-1] == "9":
    for i in range(3,10**100000,10):
        if not str(k * i).count('7') == len(str(k*i))
            continue
        else:
            print(str(k * i).count('7'))
elif str(k)[-1] == "1":
    for i in range(7,10**100000,10):
        if not str(k * i).count('7') == len(str(k*i))
            continue
        else:
            print(str(k * i).count('7'))



Fixed submission:
k = int(input())

go = 0
keta = len(str(k))

for i  in range(10**1000000):
    if k % 2 ==0:
        print(-1)
        break
    if k % 5==0:
        print(-1)
        break
    else:
        go =(go*10+7) %k
        if go ==0:
            print(i+1)
            break