//============================================================================
// Name        : main1039.cpp
// Author      : 
// Version     :
// Copyright   : Your copyright notice
// Description : Hello World in C++, Ansi-style
//============================================================================

#include <iostream>
#include <stdio.h>
#include <cstdlib>
#include <iomanip>
using namespace std;

int main() {
	while(1){
		int num;
		cin >> num;
		if(!num) return num;
		double *x = new double[num], *y = new double[num];
		for(int i = 0; i < num; i++){
			cin >> x[i] >> y[i];
		}
		double xmax = x[1];
		int indexmax = 1;
		for(int i = 0; i < num-1; i++){
			for(int j = i+1; j < num; j++){
				for(int k = 0; k <= 1; k++){
					double x1 = x[i], x2 = x[j], y1 = y[i]-k, y2 = y[j]-(1-k);
					double K = (y2-y1)/(x2-x1);
					int idx = -1;
					int l;
					double Yl;
					for(l = 0; l < num; l++){
						if(l == i || l == j) Yl = l==i? y1: y2;
						else Yl = y1 + K * (x[l]-x1);
						//cout << setprecision(32) << Yl << " " << y[l] << endl;
						if(Yl > y[l] || Yl < y[l]-1){
							idx = l-1;
							break;
						}
					}
					//cout << i << " " << j << " " << k << " " << K << " " << idx << endl;

					if(l == num) {
						indexmax = num-1;
						goto daotou;//穿过全部
					}
					if(idx < indexmax) continue;//穿过的段数不够
					indexmax = idx;
					double offset = Yl > y[idx+1]? 0: -1;
					double KK = (y[idx+1]-y[idx])/(x[idx+1]-x[idx]);
					double X = (y[idx]+offset-y1+K*x1-KK*x[idx])/(K-KK);
					if(X>xmax) xmax = X;
				}
			}
		}
		daotou:
		if(indexmax == num-1){
			cout << "Through all the pipe." << endl;
			//continue;
		}
		else{
			printf("%.2lf\n", xmax);
		}
	}
	//cout << "!!!Hello World!!!" << endl; // prints !!!Hello World!!!
	return 0;
}