/*  prog1a.c -- Determine Machine Epsilon
    Written Feb 20, 2001 by Eric Olson for Mathematics 483

    For more information see Step 3 in First Steps in Numerical
    Analysis, 2nd Edition, by Hosking, Joe, Joyce and Turner. */

#include <stdio.h>
#include <math.h>
#define REAL double
#define Rfmt "%lg"

static REAL x;

REAL bisect1(REAL a,REAL b){
    REAL delta,deold=a;
    for(;;){
        REAL r1;
        delta=(a+b)/2.0;
        if(deold==delta) break;
        r1=x+delta;
        if((REAL)r1==(REAL)x) a=delta;
        else b=delta;
        deold=delta;
    }
    return a;
}

main(){
    while(scanf(Rfmt,&x)==1){
        REAL d1=bisect1((REAL)0.0,x>0.0?x:-x);
        printf("x=" Rfmt " d1=" Rfmt "\n",x,d1);
    }
}