N = int(input())
if N==1:
    print(2)
elif N==2:
    print(3)
else:
    K = 1
    while K*K<=N:
        K += 1
    ans = N-1
    for p in range(2,K):
        a = N%p
        if a==0:continue
        x = (N-a)//p
        flag = True
        while x:
            if x%p!=a:
                flag = False
                break
            x = (x-a)//p
        if flag:
            ans = p
            break
    if ans<N-1:
        print(ans)
    else:
        M = set()
        for i in range(1,N+1):
            if i*i>N:break
            if N%i==0:
                M.add(i)
                M.add(N//i)
        M = sorted(list(M))
        for a in M:
            p = N//a-1
            if p>=K:
                ans = min(ans,p)
        print(ans)