Problem Statement

We have $N$ boxes, numbered $1$ through $N$. At first, box $1$ contains one red ball, and each of the other boxes contains one white ball.

Snuke will perform the following $M$ operations, one by one. In the $i$-th operation, he randomly picks one ball from box $x_i$, then he puts it into box $y_i$.

Find the number of boxes that may contain the red ball after all operations are performed.

Constraints

• $2 \leq N \leq 10^5$
• $1 \leq M \leq 10^5$
• $1 \leq x_i,y_i \leq N$
• $x_i \neq y_i$
• Just before the $i$-th operation is performed, box $x_i$ contains at least $1$ ball.

Input

The input is given from Standard Input in the following format:

$N$ $M$

$x_1$ $y_1$

$:$

$x_M$ $y_M$

Output

Print the number of boxes that may contain the red ball after all operations are performed.

3 2
1 2
2 3

2

Just after the first operation, box $1$ is empty, box $2$ contains one red ball and one white ball, and box $3$ contains one white ball.

Now, consider the second operation. If Snuke picks the red ball from box $2$, the red ball will go into box $3$. If he picks the white ball instead, the red ball will stay in box $2$. Thus, the number of boxes that may contain the red ball after all operations, is $2$.

3 3
1 2
2 3
2 3

1

All balls will go into box $3$.

4 4
1 2
2 3
4 1
3 4

3