```#include <string>
#include <vector>
#include <algorithm>
#include <map>
#include <set>
#include <stack>
#include <queue>
#include <math.h>
#include <iostream>
#include <fstream>
#include <stdio.h>
#include <stdlib.h>
#include <cassert>
#include <string.h>

#include <time.h>
#include <random>
#include <iomanip>
using namespace std;

#define ll long long
#define N 10005

pair<ll,ll> pts[N];

double getAngle(pair<ll,ll> a, pair<ll,ll> b, pair<ll,ll> c) {
pair<ll,ll> v1, v2;

v1 = {b.first-a.first, b.second-a.second};
v2 = {b.first-c.first, b.second-c.second};

ll dot = v1.first*v2.first + v1.second*v2.second;
ll det = v1.first*v2.second - v1.second*v2.first;

return atan2(det, dot);
}

void solve() {
ll r, n;
cin >> r >> n;
double jagged = 0;
double angle = 0;
pair<ll,ll> pt;
for (ll i = 0; i < n; i++) {
cin >> pts[i].first >> pts[i].second;
}

for (ll i = 0; i < n; i++) {
ll iP = (i-1)%n;
ll iN = (i+1)%n;
if (iP < 0)
iP += n;
jagged += sqrt(pow(pts[iP].first-pts[i].first, 2)+pow(pts[iP].second-pts[i].second,2));

double ang = getAngle(pts[iP], pts[i], pts[iN]);
if (ang < 0)
ang += 2*M_PI;
ang = abs(M_PI-ang);
//cout << ang << endl;
angle += ang;
}

double angleTotal = angle*r;

if (angleTotal > jagged)
cout << "Not possible" << endl;
else {
double factor = (jagged-angleTotal)/jagged;
cout << factor << endl;
}
}

int main() {
std::ios::sync_with_stdio(false);
cin.tie(0);
ll t;
cin >> t;
for (ll i = 0; i < t; i++) {
solve();
}
}```