#include<bits/stdc++.h>
long long n,m,a[1000001],s,num;
long long  ans;
inline int read()
{
	int x=0,f=1;char ch=getchar();
	while (ch<'0'||ch>'9'){if (ch=='-') f=-1;ch=getchar();}
	while (ch>='0'&&ch<='9'){x=x*10+ch-48;ch=getchar();}
	return x*f;
}
using namespace std;
int main(){
    n=read();
    for(int i=1;i<=n/2;i++){
        if(n%i==0) ans=i;
    }
    printf("%lld",ans);
    return 0;
}