#include <iostream>
#include <string>
#include <math.h>

using namespace std;

int main()
{
    float x;
    int n;
    string symb;

    cout << "x = ";
    cin >> x;

    cout << "N = ";
    cin >> n;

    cout << "Symbol: ";
    cin >> symb;

    int i = 2;
    float z = 1.0;
    float multi = pow(cos(x), 2) + x;

    if (symb == "f" || symb == "F") {
        for ( ; i <= n; i++) {
            z *= multi - 2.8 * sqrt(i);
        }
    } else if (symb == "w" || symb == "W") {
        while (i <= n) {
            z *= multi - 2.8 * sqrt(i);
            i++;
        }
    } else if (symb == "d" || symb == "D") {
        do {
            z *= multi - 2.8 * sqrt(i);
        } while (i++ < n);
    } else {
        cout << "НЕВЕРНЫЙ СИМВОЛ" << endl;
        return 0;
    }

    z *= log(4.8);

    cout << z << endl;

    return 0;
}