#!/bin/bash

set -euo pipefail

val=0
while read part1 part2; do
	case "$part1" in
		+)   val=$((val + part2));;
		-)   val=$((val - part2));;
		'*') val=$((val * part2));;
		/)   val=$((val / part2));;
		'')  echo $val;;
		*)   val="$part1";;
	esac
done