Problem: A crop circle suddenly appeared on the vast agricultural land of Argentina. A total of n crop circles were confirmed, including overlapping, popping, large, and small ones.

When a mystery hunter tried to capture the whole picture of a crop circle from the air, he found it difficult to show the beautiful pattern in the image because the outline of each circle was not clear.

Therefore, the mystery hunter proposed to emphasize the contour by installing a string of special material along the contour.

The part where the string is installed is the part on the circumference of one crop circle that is not included in any other crop circle.

The film crew asked you to create a program to measure the required string length. Enter the center coordinates and radius of each crop circle and create a program to report the length of the string to be installed.

For reference, the first and second cases of the input / output examples are shown in FIGS. 1 and 2, respectively. The part of the string is shown by a thick line.


<image>


Figure 1



<image>


Figure 2



Constraints

* n ≤ 100
* -1000 ≤ xi, yi ≤ 1000
* 0 <ri ≤ 100

Input

Multiple datasets are given as input. Each dataset is given in the following format:

n (number of crop circles: integer)
x1 y1 r1 (center coordinates and radius of the first circle: real numbers separated by blanks)
x2 y2 r2 (center coordinates and radius of the second circle: real numbers separated by blanks)
..
..
xn yn rn (center coordinates and radius of the nth circle: real numbers separated by blanks)


When n is 0, it indicates the end of input.

Output

Output the string length on one line for each dataset. The output may contain an error of 0.000001 or less.

Example

Input

4
6 4 2
4 7 3
7 10 3
13 6 1
4
7 4 2
4 7 3
7 10 3
11 6 3
0


Output

39.664699289572
45.627024663706

Solution (in CPP):

Solution:
#include <cstdio>
#include <cmath>
#include <cstring>
#include <cstdlib>
#include <climits>
#include <ctime>
#include <queue>
#include <stack>
#include <algorithm>
#include <list>
#include <vector>
#include <set>
#include <map>
#include <iostream>
#include <deque>
#include <complex>
#include <string>
#include <iomanip>
#include <sstream>
#include <bitset>
#include <valarray>
#include <iterator>
#include <assert.h>
using namespace std;
typedef long long int ll;
typedef unsigned int uint;
typedef unsigned char uchar;
typedef unsigned long long ull;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;

#define REP(i,x) for(int i=0;i<(int)(x);i++)
#define REPS(i,x) for(int i=1;i<=(int)(x);i++)
#define RREP(i,x) for(int i=((int)(x)-1);i>=0;i--)
#define RREPS(i,x) for(int i=((int)(x));i>0;i--)
#define FOR(i,c) for(__typeof((c).begin())i=(c).begin();i!=(c).end();i++)
#define RFOR(i,c) for(__typeof((c).rbegin())i=(c).rbegin();i!=(c).rend();i++)
#define ALL(container) (container).begin(), (container).end()
#define RALL(container) (container).rbegin(), (container).rend()
#define SZ(container) ((int)container.size())
#define mp(a,b) make_pair(a, b)
#define UNIQUE(v) v.erase( unique(v.begin(), v.end()), v.end() );

template<class T> bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T> bool chmin(T &a, const T &b) { if (a>b) { a=b; return 1; } return 0; }
template<class T> ostream& operator<<(ostream &os, const vector<T> &t) {
os<<"["; FOR(it,t) {if(it!=t.begin()) os<<","; os<<*it;} os<<"]"; return os;
}
template<class T> ostream& operator<<(ostream &os, const set<T> &t) {
os<<"{"; FOR(it,t) {if(it!=t.begin()) os<<","; os<<*it;} os<<"}"; return os;
}
template<class S, class T> ostream& operator<<(ostream &os, const pair<S,T> &t) { return os<<"("<<t.first<<","<<t.second<<")";}
template<class S, class T> pair<S,T> operator+(const pair<S,T> &s, const pair<S,T> &t){ return pair<S,T>(s.first+t.first, s.second+t.second);}
template<class S, class T> pair<S,T> operator-(const pair<S,T> &s, const pair<S,T> &t){ return pair<S,T>(s.first-t.first, s.second-t.second);}

namespace geom{
#define X real()
#define Y imag()
#define at(i) ((*this)[i])
#define SELF (*this)
	enum {TRUE = 1, FALSE = 0, BORDER = -1};
	typedef int BOOL;
	typedef double R;
	const R INF = 1e8;
	const R EPS = 1e-12;
	const R PI = 3.1415926535897932384626;
	inline int sig(const R &x) { return (abs(x) < EPS ? 0 : x > 0 ? 1 : -1); }
	inline BOOL less(const R &x, const R &y) {return sig(x-y) ? x < y : BORDER;}
	typedef complex<R> P;
	inline R norm(const P &p){return p.X*p.X+p.Y*p.Y;}
	inline R inp(const P& a, const P& b){return (conj(a)*b).X;}
	inline R outp(const P& a, const P& b){return (conj(a)*b).Y;}
	inline P unit(const P& p){return p/abs(p);}
	inline P proj(const P &s, const P &t){return t*inp(s, t)/norm(t);}
	inline int ccw(const P &s, const P &t, const P &p, int adv=0){
		int res = sig(outp(t-s, p-s));
		if(res || !adv) return res;
		if(sig(inp(t-s, p-s)) < 0) return -2;	// p-s-t
		if(sig(inp(s-t, p-t)) < 0) return 2;	// s-t-p
		return 0;								// s-p-t
	}
	
	
	struct L : public vector<P>{	// line
		L(const P &p1, const P &p2){this->push_back(p1);this->push_back(p2);}
		L(){}
		P dir()const {return at(1) - at(0);}
		BOOL online(const P &p)const {return !sig(outp(p-at(0), dir()));}
	};
	struct S : public L{	// segment
		S(const P &p1, const P &p2):L(p1, p2){}
		S(){}
		BOOL online(const P &p)const {
			if(!sig(norm(p - at(0))) || !sig(norm(p - at(1)))) return BORDER;
			return !sig(abs(at(0)-p) + abs(at(1) - p) - abs(at(0) - at(1)));
		}
	};
	struct C : public P{
		R r;
		BOOL inside(const P& p)const { return less(norm(p-SELF), r*r);}
	};
	P crosspoint(const L &l, const L &m);
	struct G : public vector<P>{
		G(size_type size=0):vector(size){}
		S edge(int i)const {return S(at(i), at(i+1 == size() ? 0 : i+1));}
		BOOL contains(const P &p)const {
			R sum = .0;
			REP(i, size()){
				if(S(at(i), at((i+1)%size())).online(p)) return BORDER;	// online
				sum += arg((at(i) - p) / (at((i+1)%size()) - p));
			}
			return !!sig(sum);
		}
		R area()const {
			R sum = 0;
			REP(i, size()) sum += outp(at(i), at((i+1)%size()));
			return abs(sum / 2.);
		}
		
		G convex_hull(bool online = false) {
			if(size() < 2) return *this;
			sort(ALL(*this));
			G r;
			r.resize((int)size()*2);
			int k=0;
			for(int i=0;i<size();r[k++]=at(i++))
				while(k>1 && ccw(r[k-2], r[k-1], at(i)) < 1-online) k--;
			int t = k;
			for(int i=(int)size()-1;i>=0;r[k++]=at(i--))
				while(k>t && ccw(r[k-2], r[k-1], at(i)) < 1-online) k--;
			r.resize(k-1);
			return r;
		}
		G cut(const L &l)const {
			G g;
			REP(i, size()){
				const S &s = edge(i);
				if(ccw(l[0], l[1], s[0], 0) >= 0) g.push_back(s[0]);
				if(ccw(l[0], l[1], s[0], 0) * ccw(l[0], l[1], s[1], 0) < 0)
					g.push_back(crosspoint(s, l));
			}
			return g;
		}
		G Voronoi(const vector<P> &p, const int t)const {
			G g = *this;
			REP(i, p.size())if(i!=t){
				const P m = (p[t]+p[i])*0.5;
				g = g.cut(L(m, m+(p[i]-p[t])*P(0, 1)));
			}
			return g;
		}
	};

	inline P proj(const P &s, const L &t){return t[0] + proj(s-t[0], t[1]-t[0]);}
	BOOL intersect(const S &s, const S &t){
		const int p = ccw(t[0], t[1], s[0], 1) * ccw(t[0], t[1], s[1], 1);
		const int q = ccw(s[0], s[1], t[0], 1) * ccw(s[0], s[1], t[1], 1);
		return (p>0||q>0) ? FALSE : (!p||!q) ? BORDER : TRUE;
	}
	BOOL intersect(const S &s, const L &l){
		if(l.online(s[0]) || l.online(s[1])) return BORDER;
		return (sig(outp(l.dir(), s[0]-l[0])) * sig(outp(l.dir(), s[1]-l[0])) <= 0);
	}
	R dist2(const L &l, const P &p){return norm(outp(l.dir(), p - l[0])) / norm(l.dir());}
	R dist2(const S &s, const P &p){
		if(inp(p-s[0],  s.dir()) < EPS) return norm(p - s[0]);
		if(inp(p-s[1], -s.dir()) < EPS) return norm(p - s[1]);
		return dist2((const L &)s, p);
	}
	R dist2(const S &s, const L &l){
		return intersect(s, l) ? .0 : min(dist2(l, s[0]), dist2(l, s[1]));
	}
	R dist2(const S &s, const S &t){
		return intersect(s, t) ? .0 : min(min(dist2(s, t[0]), dist2(t, s[0])), 
									   	  min(dist2(s, t[1]), dist2(t, s[1])));
	}
	template <class T> R dist2(const G &g, const T& t){ // todo: 内部に完全に含まれる場合
		R res = INF;
		REP(i, g.size()) res = min(res, dist2(g.edge(i), t));
		return res;
	}
	template<class S, class T> R dist(const S& s, const T& t){return sqrt(dist2(s, t));}
	inline BOOL intersect(const C &a, const C &b){
		return less((a.r-b.r)*(a.r-b.r), norm(a-b)) + less(norm(a-b), (a.r+b.r)*(a.r+b.r)) - 1;
	}
	inline BOOL intersect(const C &c, const L &l){
		return less(dist2(l, c), c.r*c.r);
	}
	inline BOOL intersect(const C &c, const S &s){
		int d = less(dist2(s, c), c.r*c.r);
		if(d != TRUE) return d;
		int p = c.inside(s[0]), q = c.inside(s[1]);
		return (p<0 || q<0) ? BORDER : p&q;
	}
	
	/*
	 * CCWでs[0]->s[1]にかけてが共通部分
	 */
	inline S crosspoint(const C &c1, const C &c2){
		if(!intersect(c1, c2)) return S();
		R d = abs(c1 - c2);
		R x = (c1.r*c1.r - c2.r*c2.r + d*d) / (2*d);
		R h = sqrt(c1.r*c1.r - x*x);
		P u = unit(c2-c1);
		return S(c1 + u*x + u*P(0,-1)*h, c1 + u*x + u*P(0,1)*h);
	}
	inline P crosspoint(const L &l, const L &m){
		R A = outp(l.dir(), m.dir()), B = outp(l.dir(), l[1] - m[0]);
		if(!sig(abs(A)) && !sig(abs(B))) return m[0]; // same line
		if(abs(A) < EPS) assert(false); // !!!PRECONDITION NOT SATISFIED!!!
		return m[0] + B / A * (m[1] - m[0]);
	}
	inline R commonarea(const C &a, const C &b){
		if(less(norm(a-b), (a.r-b.r)*(a.r-b.r)) == TRUE) return min(a.r*a.r, b.r*b.r)*PI;
		if(less((a.r+b.r)*(a.r+b.r), norm(a-b)) == TRUE) return .0;
		double d = abs(a-b);
		double rc = (d*d + a.r*a.r - b.r*b.r) / (2*d);
		double theta = acos(rc / a.r);
		double phi = acos((d - rc) / b.r);
		return a.r*a.r*theta + b.r*b.r*phi - d*a.r*sin(theta);
	}
	vector<L> CommonTangent(C c1, C c2){
		if(c1.r > c2.r) swap(c1, c2);
		double d = abs(c1-c2);
		vector<L> res;
		if(d < EPS) return res;
		if(d + EPS > c1.r + c2.r){
			// 内接線
			P crs = (c1*c2.r + c2*c1.r) / (c1.r + c2.r);
			double rad = asin(c1.r/abs(crs-c1));
			res.push_back(L(crs, crs + (c1-crs)*polar(1., rad)));
			res.push_back(L(crs, crs + (c1-crs)*polar(1., -rad)));
		}
		if(c1.r + d + EPS > c2.r){
			// 外接線
			double rad = 0.5*PI+asin((c2.r-c1.r) / d);
			P v = unit(c2-c1)*polar(1., rad);
			if(c1.r + d - EPS < c2.r){
				res.push_back(L(c1+v*c1.r, c1+v*c1.r+(c1-c2)*P(0, 1)));
			}else{
				res.push_back(L(c1+v*c1.r, c2+v*c2.r));
				v = 2.*proj(v, c2-c1) - v;
				res.push_back(L(c1+v*c1.r, c2+v*c2.r));
			}
		}
		return res;
	}
	
	
	struct Arrangement{
		struct AEdge{
			int u, v, t;
			R cost;
			AEdge(int u=0, int v=0, int t=0, R cost=0)
				:u(u), v(v), t(t), cost(cost){}
		};
		typedef vector<vector<AEdge>> AGraph;
		vector<P> p;
		AGraph g;
		Arrangement(){}
		Arrangement(vector<S> seg){
			int m = seg.size();
			REP(i, m){
				p.push_back(seg[i][0]);
				p.push_back(seg[i][1]);
				REP(j, i) if(sig(outp(seg[i].dir(), seg[j].dir())) && intersect(seg[i], seg[j]) == TRUE)
					p.push_back(crosspoint(seg[i], seg[j]));
			}
			sort(ALL(p)); UNIQUE(p);
			int n=p.size();
			g.resize(n);
			REP(i, m){
				S &s = seg[i];
				vector<pair<R, int>> ps;
				REP(j, n) if(s.online(p[j])) ps.emplace_back(norm(p[j] - s[0]), j);
				sort(ALL(ps));
				REP(j, (int)ps.size()-1){
					const int u=ps[j].second;
					const int v=ps[j+1].second;
					g[u].emplace_back(u, v, 0, abs(p[u] - p[v]));
					g[v].emplace_back(v, u, 0, abs(p[u] - p[v]));
				}
			}
		}
		
		int getIdx(P q){
			auto it = lower_bound(ALL(p), q);
			if(it == p.end() || *it != q) return -1;
			return it - p.begin();
		}
	};

	struct min_ball {
		P center;
		R radius2;
		min_ball(const vector<P>& p) {
			FOR(it, p) ps.push_back(*it);
		}
		min_ball& compile() {
			m = 0;
			center = P(0, 0);
			radius2 = -1;
			make_ball(ps.end());
			return *this;
		}
	private:
		list<P> ps;
		list<P>::iterator supp_end;
		int m;
		P v[3], c[3];
		R z[3], r[3];
		void pop() { --m; }
		void push(const P& p) {
			if (m == 0) {
				c[0] = p; r[0] = 0;
			} else {
				R e = norm(p-c[m-1]) - r[m-1];
				P delta = p - c[0];
				v[m] = p - c[0];
				for (int i = 1; i < m; ++i)
					v[m] -= v[i] * inp(v[i], delta) / z[i];
				z[m] = inp(v[m], v[m]);
				c[m] = c[m-1] + e*v[m]/z[m]*.5;
				r[m] = r[m-1] + e*e/z[m]*.25;
			}
			center	= c[m];
			radius2 = r[m]; ++m;
		}
		void make_ball(list<P>::iterator i) {
			supp_end = ps.begin();
			if (m == 3) return;
			for (list<P>::iterator k = ps.begin(); k != i; ) {
				list<P>::iterator j = k++;
				if (norm(*j-center) > radius2) {
					push(*j); make_ball(j); pop();
					move_to_front(j);
				}
			}
		}
		void move_to_front(list<P>::iterator j) {
			if (supp_end == j) ++supp_end;
			ps.splice (ps.begin(), ps, j);
		}
	};

#undef SELF
#undef at
}

using namespace geom;

namespace std{
	bool operator<(const P &a, const P &b){return sig(a.X-b.X) ? a.X < b.X : a.Y < b.Y;}
	bool operator==(const P &a, const P &b){return !sig(norm(a-b));}
	istream& operator>>(istream &is, P &p){R x,y;is>>x>>y;p=P(x, y);return is;}
	istream& operator>>(istream &is, L &l){l.resize(2);return is >> l[0] >> l[1];}
	istream& operator>>(istream &is, C &c){return is >> (P &)c >> c.r;}
}


int n;

int main(){
	ios::sync_with_stdio(false);
	while(cin >> n, n){
		vector<C> c(n);
		REP(i, n) cin >> c[i];
		R ans = 0;
		REP(i, n){
			map<R, int> imos;
			imos[PI] = 0;
			REP(j, n)if(i!=j){
				if(!sig(norm(c[i]-c[j])) && !sig(c[i].r-c[j].r)){
					if(i<j){
						imos[-PI] ++;
						break;
					}
				}else if(abs(c[i]-c[j])+c[i].r < c[j].r+EPS){
					imos[-PI] ++;
					break;
				}
				S s = crosspoint(c[i], c[j]);
				if(s.empty()) continue;
				R r0 = arg(s[0] - c[i]);
				R r1 = arg(s[1] - c[i]);
				imos[r0] ++;
				imos[r1] --;
				if(r1 < r0 - EPS) imos[-PI] ++;
			}
			R prev = -PI;
			int sum = 0;
			FOR(it, imos){
				if(!sum) ans += (it->first - prev) * c[i].r;
				sum += it->second;
				prev = it->first;
			}
		}
		printf("%.12f\n", ans);
	}
	return 0;
}