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

double func(double x){
//    return tan(x) - 4.0/3.0;
    return x*x+2.0*x+0.999999;
}

double dfdx(double x){
//    return 1.0/cos(x)/cos(x);
    return 2.0*x+2.0;
}

int step = 0;

/*
 Find x | func(x)=0 by newton method.
 acc is accuracy of the solution.
 */
double newton_method(double x1, double x2, double acc){
    double tx = (x1+x2)/2.0;
    double ftx = func(tx);
    double dftx = dfdx(tx);
    
    while(fabs(ftx)>acc){
        step++;
        printf("step:%d tx:%lf\n", step, tx);
        
        tx = tx - ftx/dftx;
        ftx = func(tx);
        dftx = dfdx(tx);
    }
    
    return tx;
}

int main(){
    double x1, x2;
    scanf("%lf %lf", &x1, &x2);
    printf("%lf\n", newton_method(x1, x2, 0.000001));
    return 0;
}