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 $i$.