**Time limit:**1.00 s**Memory limit:**512 MB

Kotivalo wants to download some data from a server. What is the maximum speed he can do this, using the connections in the network?

**Input**

The first input line has two integers $n$ and $m$: the number of computers and connections. The computers are numbered $1,2,\dots,n$. Computer $1$ is the server and computer $n$ is Kotivalo's computer.

After this, there are $m$ lines describing the connections. Each line has three integers $a$, $b$ and $c$: computer $a$ can send data to computer $b$ at speed $c$.

**Output**

Print one integer: the maximum speed Kotivalo can download data.

**Constraints**

- $1 \le n \le 500$

- $1 \le m \le 1000$

- $1 \le a,b \le n$

- $1 \le c \le 10^9$

**Example**

Input:

`4 5`

1 2 3

2 4 2

1 3 4

3 4 5

4 1 3

Output:

`6`