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.