#include <iostream>
using namespace std;

double f(double x){ return -7*x*x - 4*x;} 
int main() {
double x1 = -0.57143,  sum = 0, dx = 0.01;
	while(x1 <= 0) {
x1 += dx; 
sum += f(x1)*dx;
} 
cout << sum;
	return 0;
}