#include <iostream>
#include <cmath>
using namespace std;
 
double tangent(double x, double accuracy) {
	int i = 1;
	double cos = 1, sin = x, intermediateValueCos = 1, intermediateValueSin = x;
	x = fmod(x, M_PI);
	while (fabs(intermediateValueCos *= - x * x / (2 * i * (2 * i - 1))) > accuracy 
		&& fabs(intermediateValueSin *= - x * x / (2 * i * (2 * i + 1))) > accuracy) {
		cos += intermediateValueCos;
		sin += intermediateValueSin;
		i++;
	}
	return sin / cos;
}
 
int main() {
	double x, accuracy;
	cin >> x >> accuracy;
	cout << tangent(x, accuracy);
	return 0;
}

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My4xNDE1

3.1415