URI Online Judge | 1128
# Come and Go

**Timelimit: 1**

Maratona de Programação da SBC Brazil

In a certain city there are *N* intersections connected by one-way and two-way streets. It is a modern city, and several of the streets have tunnels or overpasses. Evidently it must be possible to travel between any two intersections. More precisely given two intersections *V* and *W* it must be possible to travel from *V* to *W* and from *W* to *V*.

Your task is to write a program that reads a description of the city street system and determines whether the requirement of connectedness is satisfied or not.

The input contains several test cases. The first line of a test case contains two integers *N* and *M*, separated by a space, indicating the number of intersections (2 ≤ **N** ≤ 2000) and number of streets (2 ≤ **M** ≤ **N**(**N**−1)/2). The next *M* lines describe the city street system, with each line describing one street. A street description consists of three integers *V*, *W* and *P*, separated by a blank space, where *V* and *W* are distinct identifiers for intersections (1 ≤ **V**, **W** ≤ **N** , **V** ≠ **W** ) and *P* can be 1 or 2; if *P* = 1 the street is one-way, and traffic goes from *V* to *W*; if *P* = 2 then the street is two-way and links *V* and *W*. A pair of intersections is connected by at most one street.

The last test case is followed by a line that contains only two zero numbers separated by a blank space.

For each test case your program should print a single line containing an integer *G*, where *G* is equal to one if the condition of connectedness is satisfied, and *G* is zero otherwise.

Input Sample | Output Sample |

4 5 |
1 |