Problem Statement

We have five variables $x_1, x_2, x_3, x_4,$ and $x_5$.

The variable $x_i$ was initially assigned a value of $i$.

Snuke chose one of these variables and assigned it $0$.

You are given the values of the five variables after this assignment.

Find out which variable Snuke assigned $0$.

Constraints

• The values of $x_1, x_2, x_3, x_4,$ and $x_5$ given as input are a possible outcome of the assignment by Snuke.

Input

Input is given from Standard Input in the following format:

$x_1$ $x_2$ $x_3$ $x_4$ $x_5$

Output

If the variable Snuke assigned $0$ was $x_i$, print the integer $i$.

Sample Input 1

0 2 3 4 5

Sample Output 1

1

In this case, Snuke assigned $0$ to $x_1$, so we should print $1$.

Sample Input 2

1 2 0 4 5

Sample Output 2

3