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>

int main()
{
    struct P {
        float x, y;
    };
    
    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;
            
            {
                auto rm_it = std::remove_if(ufos.begin(), ufos.end(), [R, a](auto& elem){
                    float d = std::abs(-a * elem.x + elem.y) / std::sqrt(a * a + 1);
                    return elem.r >= d;
                });
                ufos.erase(rm_it, ufos.end());
            }
        }
        printf("%d\n", count);
    }
}

C++: #include <iostream>
#include <cmath>

using namespace std;

struct UFO {
	double x, y, r, v, dist2;
	bool flag;
} ufo[100];

int main() {
	int N, R;

	while (cin >> R >> N, R || N) {
		for (int i = 0; i < N; ++i) {
			cin >> ufo[i].x >> ufo[i].y >> ufo[i].r >> ufo[i].v;
			ufo[i].flag = true;
			ufo[i].dist2 = ufo[i].x*ufo[i].x + ufo[i].y*ufo[i].y;
		}

		while (1) {
			int ans = 0;
			bool flag = true;
			for (int i = 0; i < N; ++i) {
				if (!ufo[i].flag) continue;
				if (ufo[i].dist2 <= R*R)
					++ans;
				else {
					flag = false;
					break;
				}
			}
			if (flag) {
				cout << ans << endl;
				break;
			}

			//UFOを移動
			for (int i = 0; i < N; ++i) {
				if (!ufo[i].flag) continue;

				if (ufo[i].x == 0.0) {
					if (ufo[i].y > 0.0) {
						ufo[i].y -= ufo[i].v;
					}
					if (ufo[i].y < 0.0) {
						ufo[i].y += ufo[i].v;
					}
				}
				else {
					double tmp = atan2(ufo[i].y, ufo[i].x);
					ufo[i].x -= ufo[i].v * cos( tmp );
					if (ufo[i].y != 0.0)
						ufo[i].y -= ufo[i].v * sin( tmp );
				}

				ufo[i].dist2 = ufo[i].x*ufo[i].x + ufo[i].y*ufo[i].y;
			}

			//レーザー発射
			int target = -1;
			for (int i = 0; i < N; ++i) {
				if (!ufo[i].flag || ufo[i].dist2 <= R*R) continue;

				if (target < 0) {
					target = i;
				}
				else if (ufo[i].dist2 < ufo[target].dist2) {
					target = i;
				}
			}
			ufo[target].flag = false;
			for (int i = 0; i < N; ++i) {
				if (!ufo[i].flag || ufo[i].dist2 <= R*R) continue;
				
				double targetdist2;	//UFOの中心とレーザーの距離
				if (ufo[target].x == 0.0)
					targetdist2 = ufo[i].x*ufo[i].x;
				else
					targetdist2 = (-ufo[target].y*ufo[i].x + ufo[target].x*ufo[i].y)*(-ufo[target].y*ufo[i].x + ufo[target].x*ufo[i].y) / ufo[target].dist2;
				
				if (targetdist2 <= ufo[i].r*ufo[i].r)
					ufo[i].flag = false;
			}
		}
	}

	return 0;
}