B bsuir 1803232021

#include <iostream>
#include <unordered_map>
#include <algorithm>
#include <set>
#include <iomanip>
#include <string>

using namespace std;

double n, m, k;

bool canUse(double val) {
    return (k <= (long long)(n / val) * (long long)(m/val));
}
int main()
{
    cin.tie(NULL);
    cout.tie(NULL);
    ios_base::sync_with_stdio(false);
    cout << fixed << setprecision(10);

    cin >> n >> m >> k;
    //NADO K SHTUK!

    double l = 0.000001, r = 1001, prev = 99999999999;
    while (abs(((l + r) / 2.0) - prev) > 0.000001) {
        double m = (l + r) / 2.0;

        if (canUse(m))
            l = m;
        else
            r = m;
        prev = m;
    }
    cout << (l + r) / 2.0;

    return 0;
}