九度oj1166

#include<stdio.h>int main(){	double x,y;	int i,n;	while (scanf("%lf%d", &x, &n) != EOF){		y = x;		i = 0;		while (i<n){			y = 2 * y / 3 + x / (3 * y*y);			i++;		}				PRintf("%.6f/n", y);	}	return 0;}