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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

$2≤N≤10^5$
$1≤M≤10^5$
$1≤x_i,y_i≤N$
$x_i≠y_i$
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.

Sample Input 1

3 2
1 2
2 3

Sample Output 1

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 $2$.

Sample Input 2

Sample Output 2

All balls will go into box $3$.

Sample Input 3