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

char*mmap();
#define rd(v) long v=0;{int _c;while(_c=*rp++-48,_c>=0)v=v*10+_c;}

#define wt_rev(v) {long _z=v;do*--wp=_z%10+48;while(_z/=10);}

main(){
	char*rp=mmap(0l,1l<<12,1,2,0,0ll);
	rd(n);
	long r=0;
	
	if(n%3==0){
		r=3;
		goto end;
	}
	if(n%2==0){
		n/=2;
	}
	if(n%2==0){
		r=4;
		goto end;
	}

	for(long i=(long)__builtin_sqrt(n)/6*6+7;i>=5;){
		{
			unsigned long x=-i;
			x*=x*i+2;
			x*=x*i+2;
			x*=x*i+2;
			x*=x*i+2;
			x*=x*i+2;
			if((__uint128_t)(x*-n)*i>>64==0){
				r=i;
			}
			i-=2;
		}
		{
			unsigned long x=-i;
			x*=x*i+2;
			x*=x*i+2;
			x*=x*i+2;
			x*=x*i+2;
			x*=x*i+2;
			if((__uint128_t)(x*-n)*i>>64==0){
				r=i;
			}
			i-=4;
		}
	}
	if(r==0){
		r=n;
		if(n%2==0){
			r/=2;
		}
	}
	
	end:;
	char wbuf[32],*wp=(wbuf+sizeof wbuf);
	wt_rev(r);
	write(1,wp,(wbuf+sizeof wbuf)-wp);
	_exit(0);
}