#include <iostream>
#include <cmath>

using namespace std;

float suma(int, float);
int main()
{
	int n;
	float x;

	cin >> n;
	while (n < 0)
	{
		cin >> n;
	}
	cin >> x;
	cout << "Suma: " << suma(n, x) << endl;
	system("PAUSE");
	return 0;
}

float suma(int n, float x)
{
	float sum = 0;
	for (int i = 1; i <= n; i++)
	{
		sum = sum + pow(sin(x),i);
	}
	return sum;
}