Sum with 13 Skip

Background

Congcong is playing a number game. He finds that the number $13$ always seems to bring bad luck, so he decides that when calculating a sum, if he encounters $13$, he will skip it and all subsequent numbers to its right.

Problem Description

Given three integer values, $a, b, c$, return their sum. However, if one of the values is $13$, then it does not count towards the sum and values to its right do not count. So for example, if $b$ is $13$, then both $b$ and $c$ do not count.

Input Format

Input is given from Standard Input in the following format.

$a$ $b$ $c$

Output Format

Output is printed to Standard Output in the following format.

Their sum

Sample

1 2 3

6

1 2 13

3

1 13 3

1

Sample Explanation

Sample 1: $a=1, b=2, c=3$. No number is $13$, so the sum is $1+2+3=6$.

Sample 2: $a=1, b=2, c=13$. $c$ is $13$, so $c$ does not count towards the sum. The sum is $1+2=3$.

Sample 3: $a=1, b=13, c=3$. $b$ is $13$, so both $b$ and $c$ do not count towards the sum. The sum is $1$.

Constraints

Time limit: 1 second, Memory limit: 1024KB.