#!/bin/bash

read line
positions=( ${line//,/ } )
min_consumption=-1
max_coordinate=-1
consumptions=( 0 )
for position in ${positions[@]}; do
  if [ $max_coordinate -eq -1 ] || [ $position -gt $max_coordinate ]; then
    max_coordinate=$position
  fi
done
for i in $(seq $max_coordinate); do
  consumptions+=( $((consumptions[i-1]+i)) )
done
for i in $(seq 0 $max_coordinate); do
  curr_consumption=0
  for position in ${positions[@]}; do
    temp_curr_consumption=$((position-i))
    temp_curr_consumption=${temp_curr_consumption#-}
    curr_consumption=$((curr_consumption+consumptions[temp_curr_consumption]))
  done
  if [ $min_consumption -eq -1 ] || [ $curr_consumption -lt $min_consumption ]; then
    min_consumption=$curr_consumption
  fi
done
echo $min_consumption