#include <stdio.h>
#include <math.h>

int main ()
{
    double x, power, result;
    int n, neg_one;

    printf("Input n (must be an integer): ");
    scanf(" %d", &n);

    printf("Input x (a number with a floating decimal point): ");
    scanf(" %lf", &x);

    result = 1;
    neg_one = -1;

    for (int i = 0; i < n; i++) {

        power = pow(x, 2*i + 1);

        neg_one *= -1;

        result *= (power*neg_one) / (2*i + 1);
    }

//    result_cos *= x;

    printf("Y = %f\n", result);
    
    return 0;
}