#include<iostream>
#include<fstream>
using namespace std;

int S1(int k)
{
    return k/10;
}

int S2(int k)
{
    int d;
    if(k<2)return 0;
    for(d=2;d<=k/2;d++)
        if(k%d==0) return 0;
    return 1;
}

int main()
{
    int x;
    ifstream f("date.in");

    while(f>>x)
    {
        while(S2(x)==0 && x>0)
            x=S1(x);
        cout<<x<<" ";
    }
}