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

double sine(double x) {
    double result = 0.0;
    double term = x; // First term x^1/1!
    int n = 1;

    while (fabs(term) >= 1e-10) {
        result += term;
        term = -term * x * x / ((2 * n) * (2 * n + 1));
        n++;
    }

    return result;
}

int main() {
    double angle_degrees;
    if (scanf("%lf", &angle_degrees) != 1) {
        printf("Invalid input\n");
        return 0;
    }

    // Convert degrees to radians
    double angle_radians = angle_degrees * M_PI / 180.0;

    double result = sine(angle_radians);

    printf("%.10lf\n", result);

    return 0;
}