#include <bits/stdc++.h>
using namespace std;

bool isPrime(int n)
{
    if (n <= 1)
        return false;
    if (n <= 3)
        return true;
    if (n % 2 == 0 || n % 3 == 0)
        return false;

    for (int i = 5; i * i <= n; i = i + 6)
        if (n % i == 0 || n % (i + 2) == 0)
            return false;

    return true;
}

// Driver Program to test above function
int main()
{
    int num;
    cin>>num;
    for(int i=num; i>=1; i--)
    {
        if(isPrime(i))
        {
            cout <<"Prime = "<<i<<endl;
            break;
        }
        else continue;
    }
    return 0;
}