Go: package main

import (
	"bufio"
	"os"
	"math"
	"strings"
	"strconv"
	"fmt"
)

var scanner = bufio.NewScanner(os.Stdin)

const (
	INF = 0x7FFFFFFF
	EPS = 1e-10
)

type Point struct {
	x, y float64
}
func (p *Point) plus(q *Point) *Point {
	return &Point{p.x + q.x, p.y + q.y}
}
func (p *Point) minus(q *Point) *Point {
	return &Point{p.x - q.x, p.y - q.y}
}
func (p *Point) multi(a float64) *Point {
	return &Point{p.x * a, p.y * a}
}
func (p *Point) div(a float64) *Point {
	return &Point{p.x / a, p.y / a}
}
func (p *Point) abs() float64 {
	return math.Sqrt(p.norm())
}
func (p *Point) norm() float64 {
	return p.x*p.x + p.y*p.y
}
func (p *Point) isLessThan(q *Point) bool {
	if p.x != q.x {
		return p.x < q.x && p.y < q.y
	}
	return true
}
func (p *Point) isEqual(q *Point) bool {
	return math.Abs(p.x - q.x) < EPS && math.Abs(p.y - q.y) < EPS
}

type Segment struct {
	p1, p2 *Point
}
func (s *Segment) norm() float64 {
	return (s.p2.x - s.p1.x)*(s.p2.x - s.p1.x) +
		(s.p2.y - s.p1.y)*(s.p2.y - s.p1.y)
}
func (s *Segment) abs() float64 {
	return math.Sqrt(s.norm())
}

func norm(a *Point) float64 {
	return a.x*a.x + a.y*a.y
}

func abs(a *Point) float64 {
	return math.Sqrt(norm(a))
}

func polar(a, r float64) *Point {
	return &Point{math.Cos(r)*a, math.Sin(r)*a}
}

func getDistance(a, b *Point) float64 {
	return abs(a.minus(b))
}

func dot(a, b *Point) float64 {
	return a.x*b.x + a.y*b.y
}

func cross(a, b *Point) float64 {
	return a.x*b.y - a.y*b.x
}

func getDistanceLP(s Segment, p *Point) float64 {
	return cross(s.p2.minus(s.p1), p.minus(s.p1))/ abs(s.p2.minus(s.p1))
}

func getDistanceSP(s Segment, p *Point) float64 {
	if dot(s.p2.minus(s.p1), p.minus(s.p1)) < 0 {
		return abs(p.minus(s.p1))
	}
	if dot(s.p1.minus(s.p2), p.minus(s.p2)) < 0 {
		return abs(p.minus(s.p2))
	}
	return getDistanceLP(s, p)
}

func main() {
	for scanner.Scan() {
		buf := strings.Split(scanner.Text(), " ")
		R, _ := strconv.Atoi(buf[0])
		N, _ := strconv.Atoi(buf[1])
		if R == 0 && N == 0 {
			break
		}
		p := make([]*Point, N)
		r := make([]float64, N)
		v := make([]float64, N)
		d := make([]float64, N)
		nd := make([]float64, N)
		die := make([]bool, N)
		for i := 0; i < N; i++ {
			scanner.Scan()
			buf_ := strings.Split(scanner.Text(), " ")
			_x, _ := strconv.ParseFloat(buf_[0], 64)
			_y, _ := strconv.ParseFloat(buf_[1], 64)
			_r, _ := strconv.ParseFloat(buf_[2], 64)
			_v, _ := strconv.ParseFloat(buf_[3], 64)
			tmp := &Point{_x, _y}
			p[i] = tmp
			r[i] = _r
			v[i] = _v
			nd[i] = getDistance(p[i], &Point{0, 0})
			d[i] = getDistance(p[i], &Point{0, 0})
			die[i] = false
		}
		for {
			for i := 0; i < N; i++ {
				nd[i] = math.Max(float64(R), nd[i]-v[i])
			}
			mini := float64(INF)
			id := -1
			for i := 0; i < N; i++ {
				if die[i] {
					continue
				}
				if nd[i] < EPS+float64(R) {
					continue
				}
				if nd[i] > mini {
					continue
				}
				mini = nd[i]
				id = i
			}
			if id == -1 {
				break
			}
			s := Segment{p[id], p[id]}
			s.p1 = s.p1.div(d[id])
			s.p1 = s.p1.multi(float64(R))
			s.p2 = s.p2.div(d[id])
			s.p2 = s.p2.multi(10000000.0)
			for i := 0; i < N; i++ {
				if nd[i] < EPS + float64(R) {
					continue
				}
				a := p[i]
				a = a.div(d[i])
				a = a.multi(nd[i])
				if getDistanceSP(s, a) < EPS + r[i] {
					die[i] = true
				}
			}
		}
		ans := 0
		for i := 0; i < N; i++ {
			if !die[i] {
				ans++
			}
		}
		fmt.Println(ans)
	}
}

C++: // This file is a "Hello, world!" in C++ language by GCC for wandbox.
#include <iostream>
#include <cstdlib>
#include <vector>
#include <cmath>
#include <algorithm>
#include <complex>

typedef std::complex<double> Point;
 
const double Eps = 1e-8;
 
double dot(const Point& a, const Point& b)
{
    return a.real()*b.real() + a.imag()*b.imag();
}
double cross(const Point& a, const Point& b)
{
    return a.real()*b.imag() - a.imag()*b.real();
}
double distance_line_point(const Point& point, const Point& a, const Point& b)
{
    return abs(cross(a-b, point-b) / (a-b));
}
double distance_linesegment_point(const Point& point, const Point& a, const Point& b)
{
    if (dot(b-a, point-a) < 0)
        return abs(a-point);
    else if (dot(a-b, point-b) < 0)
        return abs(b-point);
    else
        return distance_line_point(point, a, b);
}

int main()
{
    struct UFO {
        float x, y;
        float v;
        float r;
        float sita;
        float d;
    };
    
    while (true) {
        int count = 0;
        int R, N;
        std::cin >> R >> N;
        
        if (R == 0 && N == 0) {
            break;
        }
        
        std::vector<UFO> ufos(N);
        
        for (int i = 0; i < N; i++) {
            std::cin >> ufos[i].x >> ufos[i].y >> ufos[i].r >> ufos[i].v;
            ufos[i].sita = std::atan2(ufos[i].y, ufos[i].x);
            ufos[i].d = std::sqrt(ufos[i].x * ufos[i].x + ufos[i].y * ufos[i].y);
        }
        
        while (!ufos.empty()) {
            for (std::size_t i = 0; i < ufos.size(); i++) {
                ufos[i].d = std::max(ufos[i].d - ufos[i].v, 0.0f);
                ufos[i].x = std::cos(ufos[i].sita) * ufos[i].d;
                ufos[i].y = std::sin(ufos[i].sita) * ufos[i].d;
            }
            
            count += std::count_if(ufos.begin(), ufos.end(), [R](auto& elem){
                return elem.d <= R;
            });
            
            {
                auto rm_it = std::remove_if(ufos.begin(), ufos.end(), [R](auto& elem){
                    return elem.d <= R;
                });
                ufos.erase(rm_it, ufos.end());
            }
            
            std::sort(ufos.begin(), ufos.end(), [](auto& lhs, auto& rhs){
                return lhs.d < rhs.d;
            });
            
            if (ufos.empty()) {
                break;
            }
            
            float a = ufos[0].y / ufos[0].x;
            {
                
                float shot_angle = std::atan2(ufos[0].y, ufos[0].x);
                auto rm_it = std::remove_if(ufos.begin(), ufos.end(), [shot_angle, R, a, &ufos](auto& elem){
                    return distance_linesegment_point(Point(elem.x, elem.y), 
                                               Point(1e10*cos(shot_angle), 1e10*sin(shot_angle)), 
                                               Point(R*cos(shot_angle), R*sin(shot_angle))) < elem.r + Eps;
                    //return elem.r >= d + 1e-6 && (ufos[0].sita * elem.sita) >= 0;
                });
                ufos.erase(rm_it, ufos.end());
            }
        }
        printf("%d\n", count);
    }
}

C++: #include <algorithm>
#include <cctype>
#include <cstdio>
#include <cmath>
#include <iostream>
#include <functional>
#include <queue>
#include <string>
#include <map>
#include <vector>

using namespace std;

struct ufo {
  double x, y, r, vx, vy;
  bool alive;
};

struct ufo ufos[100];

double sq(double x) {
  return x*x;
}

int main() {
  for (;;) {
    int R, N;
    cin >> R >> N;
    if (!R && !N) return 0;
    for (int i = 0; i < N; i++) {
      double v;
      cin >> ufos[i].x >> ufos[i].y >> ufos[i].r >> v;
      double l = sqrt(sq(ufos[i].x)+sq(ufos[i].y));
      ufos[i].vx = -ufos[i].x*v/l;
      ufos[i].vy = -ufos[i].y*v/l;
      ufos[i].alive = true;
    }
    int alive = N, result = 0;
    while (alive) {
      int f = 0;
      double m = 1500;
      for (int i = 0; i < N; i++)
        if (ufos[i].alive) {
          ufos[i].x += ufos[i].vx;
          ufos[i].y += ufos[i].vy;
          double l = sqrt(sq(ufos[i].x)+sq(ufos[i].y));
          if (l <= R) {
            ufos[i].alive = false;
            alive--;
            result++;
          } else if (l < m) {
            m = l;
            f = i;
          }
        }
      if (!alive) break;
      for (int i = 0; i < N; i++)
        if (ufos[i].alive &&
            abs(ufos[i].x*ufos[f].y-ufos[i].y*ufos[f].x)/m <= ufos[i].r) {
          ufos[i].alive = false;
          alive--;
        }
    }
    cout << result << endl;
  }
}