#include <bits/stdc++.h>
#define ull unsigned long long
#define ll long long
#define el endl
#define nl '\n'
#define all(v) v.begin(), v.end()
using namespace std;

void input()
{
    if (fopen("in.txt", "r"))
    {
        freopen("in.txt", "r", stdin);
        freopen("out.txt", "w", stdout);
    }
}

void init()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
}
int main()
{
Fast:
    input();
    init();
    //---------------------------------------------------------------------------------------------------------------
    int n;
    cin >> n;
    if (n * -1 == -n)
    {
        cout << n << nl;
    }
    else
        cout << "enter another one (pos) ." << nl;

    return 0;
}