import sys

# sys.setrecursionlimit(200005)
# sys.set_int_max_str_digits(200005)
int1 = lambda x: int(x)-1
pDB = lambda *x: print(*x, end="\n", file=sys.stderr)
p2D = lambda x: print(*x, sep="\n", end="\n\n", file=sys.stderr)
def II(): return int(sys.stdin.readline())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]
def LI1(): return list(map(int1, sys.stdin.readline().split()))
def LLI1(rows_number): return [LI1() for _ in range(rows_number)]
def SI(): return sys.stdin.readline().rstrip()

dij = [(0, 1), (-1, 0), (0, -1), (1, 0)]
# dij = [(0, 1), (-1, 0), (0, -1), (1, 0), (1, 1), (1, -1), (-1, 1), (-1, -1)]
# inf = -1-(-1 << 31)
inf = -1-(-1 << 62)

# md = 10**9+7
md = 998244353

def gcd(a, b):
    while b: a, b = b, a%b
    return a

def extgcd(x, y):
    a, b = 1, 0
    while y:
        a, b = b, (a-x//y*b)
        x, y = y, x%y
    return a

def BabyGiant(a, b, md):
    a, b = a%md, b%md

    if md == 1: return 1
    # if a == b == 0: return 1
    # if b == 1: return 0

    # baby step
    m = int(md**.5)+1
    baby = {}
    x = 1
    for i in range(1,m+1):
        x = x*a%md
        if x not in baby:baby[x] = i
    if b in baby:
        return baby[b]

    # giant step
    inv = extgcd(x, md)
    for i in range(1, m+1):
        b = b*inv%md
        if b in baby:
            return i*m+baby[b]
    return -1

print(BabyGiant(10, 1, II()))