n=int(input())
ans=n-1
for i in range(2,10**6):
    c=n
    d=c%i;f=1
    while c:
        if c%i!=d:
            f=0;break
        c//=i
    if f:
        print(i);exit()
for i in range(1,10**6+1):
    q,w=2,n
    while w-q>1:
        m=(q+w)//2
        if m*i+i<=n:
            q=m
        else:
            w=m
    if q*i+i==n:
        ans=min(ans,q)
print(ans)