#include <stdio.h>
#include <math.h>
float a, b;
float f(float x)
{
    return a*x+b;
}
int main()
{
    freopen(".10.in","r",stdin);
    freopen(".10.out","w",stdout);
    scanf("%f%f", &a, &b);
    float lb = -999.0, ub = 999.0;
    while( lb < ub )
    {
        float x = (lb+ub)/2.0;
        if( fabs(f(x)) <= (1e-7) )
        {
            printf("%.4f\n", x);
            return 0;
        }
        if( f(x) > 0 ) ub = x;
        else lb = x;
    }
}