#include<stdio.h> int main() { double x,x1,x2,w; scanf("%lf",&x); x1=x; x2=(2.0*x1+x/(x1*x1))/3.0; w=(x2-x1)/x1; if(w<0) w=w*-1; while(w>=1e-6) { x1=x2; x2=(2*x1+x/(x1*x1))/3.0; w=(x2-x1)/x1; if(w<0) w=w*-1; } printf("%f ",x2); }