#pragma GCC optimize("Ofast")
#pragma GCC target("avx2")

double sqrt(double);

main(){
	long n;
	scanf("%ld",&n);
	long s=(long)sqrt(n)+2;

	for(long p=2;p<s;++p){
		long d=n%p;
		long x=n;
		while(x/=p){
			if(x%p!=d){
				goto l1;
			}
		}
		printf("%ld",p);
		exit(0);
		l1:;
	}

	for(long q=s;--q;){
		if(n%q==0){
			long p=n/q-1;
			if(q<p){
				printf("%ld",p);
				exit(0);
			}
		}
	}

	printf("%ld",n+1);
}