#include <bits/stdc++.h>

using namespace std;

typedef pair<int, int> pii;
typedef long long ll;
const int N = 2000086, MOD = 1e9 + 7, INF = 0x3f3f3f3f;
ll res;
int n, m, cnt, w[N];


int main() {
    int a, b, c;
    cin >> a >> b >> c;
    if (a > c) swap(a, c);
    if (b > c) swap(b, c);
    double p = (double)(a + b + c) / 2;
    double sum = sqrt(p * (p - a) * (p - b) * (p - c));
    printf("%.8lf\n", 2 * sum / (a + b + c));
    return 0;
}