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

int32_t main()
{
    int  n;
    cin >> n;
    int a = sqrt(n);
    if(a * a == n)
        cout << n;
    else
    {
        a ++;
        if(a == 1000000001)
        {
            cout << 1000000000000000000;
            return 0;
        }
        if(n <= (a - 1) * (a - 1))
        {
            cout << (a - 1) * (a - 1);
            return 0;
        }
        if(n > a * a)
        {
            cout << (a + 1) * (a + 1);
            return 0;
        }
        cout << a * a;
    }
}