// @BEGIN_OF_SOURCE_CODE

/* @JUDGE_ID:  17243NT  149  C++  "Trig" */

// Send to judge@uva.es

#include <iostream.h>
#include <fstream.h>
#include <math.h>

#ifdef ONLINE_JUDGE
	#define ins cin
	#define outs cout
#else
	#define ins fin
	#define outs fout
	ifstream fin("myprog.in");
	ofstream fout("myprog.out");
#endif

void calculate(double h, double k);

const double SIN005 = 0.00087266451523514954330458929907378;
const double PI = 3.1415926535897932384626433832795;

typedef struct {
	double a1, a2;
} tree;

tree tarray[1000000];
int ntree;
int nsol;

double radius;
double maxdist, distsquare;

tree newtree(double h, double k) {
	tree t;

	double angle = atan(h / k) / PI * 180;
	double mangle = atan(radius /
		sqrt(h * h + k * k - radius * radius)) / PI * 180;

	t.a1 = angle - mangle;
	t.a2 = angle + mangle;

	return t;
}

bool isbetween(tree t1, tree t2) {
	if(t1.a1 - 0.01 <= t2.a1 && t2.a1 <= t1.a2 + 0.01)
		return true;
		
	if(t1.a1 - 0.01 <= t2.a2 && t2.a2 <= t1.a2 + 0.01)
		return true;
	
	return false;
}

void quadrant(double ox, double oy) {
	double x, y;
	double t;
	int i, c = 0;
	
	if(ox * ox + oy * oy > distsquare)
		return;
	
	y = oy;
	t = sqrt(distsquare - y * y);
	for(x = ox; x <= t; x++) {
		tree t = newtree(x, y);
		
		for(i = 0; i < ntree; i++)
			if(isbetween(tarray[i], t)) {
				break;
			}
		
		if(i >= ntree) {
			nsol++;
			c++;
		}

		tarray[ntree++] = t;
	}

	x = ox;
	t = sqrt(distsquare - x * x);
	for(y = oy + 1; y <= t; y++) {
		tree t = newtree(x, y);
		
		for(i = 0; i < ntree; i++)
			if(isbetween(tarray[i], t)) {
				break;
			}
		
		if(i >= ntree) {
			nsol++;
			c++;
		}

		tarray[ntree++] = t;
	}
	
	quadrant(ox + 1, oy + 1);
}

int main() {
	double diam;
	double ox, oy;
	
	while(ins >> diam >> ox >> oy) {
		if(diam == 0) break;
		radius = diam / 2;
		maxdist = radius / SIN005;
		distsquare = maxdist * maxdist;
		
		nsol = 0;

		ntree = 0;
		quadrant(1 - ox, 1 - oy);

		ntree = 0;
		quadrant(1 - ox, oy);

		ntree = 0;
		quadrant(ox, 1 - oy);

		ntree = 0;
		quadrant(ox, oy);

		cout << nsol << endl;
	}
	
	return 0;
}

// @END_OF_SOURCE_CODE