#!/bin/bash

# Create a temp file to save the right column in so it can be easily searched with grep.
right_file=$(mktemp)

# Use awk to separate the columns.
left=$(awk '{print $1}' input.txt)
awk '{print $2}' input.txt > $right_file

# Initialize the similarity score.
similarity_score=0

for entry in $left; do

    # Count the number of times each ID from the left column occurs in the right column.
    count=$(cat $right_file | grep $entry | wc -l)

    # Multiply the count by the ID value, and add that the the cumulative sum.
    similarity_score=$((count * entry + similarity_score))
done

echo $similarity_score


# for l in $left; do
#     echo $l
# done