n=int(input()) def zx(a): k=2 while k<a: if a%k==0: return 0 elif k==a-1: return 1 k=k+1

i=2 while i<n: if n%i==0 and zx(i)==1: s=n//i if zx(s)==1: print(s) break else: print(i) break i+=1