#include <iostream>
#include <cmath>
#include <math.h>
using namespace std;
int main() {
    double m, s, r, n, p, k;
    cout << "Vvedite summu zayma" << endl;
    cin >> s;
    cout << "Vvedite procent" << endl;
    cin >> p;
    cout << "Vvedite kol-vo let" << endl;
    cin >> n;
    r = p / 100;
    k = pow(1 + r, n);
    m = s * r * k / (12 * (k - 1));
    cout << m;
    return 0;
}