#include <bits/stdc++.h> using namespace std; int main() { double n, m, k, l, r, mid; cin >> n >> m >> k; l = 00.0; r = 10.0; while (r - l >= 0.0001) { mid = (l + r) / 2; if (pow(1.0 / (1.0 + mid), k) >= 1 - n / m * mid) { r = mid; } else { l = mid; } } cout << fixed << setprecision(1) << l * 100 << endl; return 0; }