#!/bin/bash

max_i=0
max_j=0
declare -A grid
while read line; do
  max_j=${#line}
  for ((j=0;j<max_j;j++)); do
    if [[ ${line:$j:1} == '.' ]]; then
      grid[$max_i,$j]=0
    elif [[ ${line:$j:1} == '>' ]]; then
      grid[$max_i,$j]=1
    elif [[ ${line:$j:1} == 'v' ]]; then
      grid[$max_i,$j]=2
    fi
  done
  max_i=$((max_i+1))
done

changes=1
south=0
steps=0
while [ $changes -eq 1 ]; do
  changes=$south
  declare -A new_grid
  for ((i=0;i<max_i;i++)); do
    for ((j=0;j<max_j;j++)); do
      if [ $south -eq 0 ] && [ ${grid[$i,$j]} -eq 1 ] && [ ${grid[$i,$(((j+1)%max_j))]} -eq 0 ]; then
        new_grid[$i,$j]=0
        new_grid[$i,$(((j+1)%max_j))]=1
        changes=1
      elif [ $south -eq 1 ] && [ ${grid[$i,$j]} -eq 2 ] && [ ${grid[$(((i+1)%max_i)),$j]} -eq 0 ]; then
        new_grid[$i,$j]=0
        new_grid[$(((i+1)%max_i)),$j]=2
        changes=1
      elif [ -z ${new_grid[$i,$j]} ]; then
        new_grid[$i,$j]=${grid[$i,$j]}
      fi
    done
  done
  south=$((1-south))
  for ((i=0;i<max_i;i++)); do
    for ((j=0;j<max_j;j++)); do
      grid[$i,$j]=${new_grid[$i,$j]}
    done
  done
  unset new_grid
  steps=$((steps+south))
done

echo $steps