What is the mistake?
n = int(input())
a = []
for i in range(1, n+1):
    if n % i == 0:
        a.append(i)
if n == 1:
    print("1")
    exit(0)
if n == 0:
    print("10")
    exit()
if len(a) > 2:
    for i in range(len(a) - 1):
        if a[i] * a[i + 1] == n or a[i]*a[i] == n:
            if a[i] * a[i + 1] == n:
                s = "".join(sorted(str(a[i])+str(a[i+1])))
                print(s)
            else:
                print(a[i], a[i], sep="")
else:
    print("-1")