#!/usr/bin/env python

import math

MAP = []
START = (0, 0)
END = (0, 0)
DISTANCES = {}

def possible(x, y):
    global MAP

    threshold = MAP[y][x] + 1 # Can't go higher than this, can always go lower
    points = [(x-1,y),(x+1,y),(x,y-1),(x,y+1)]

    out = []
    for (x,y) in points:
        if x < 0 or y < 0:
            continue
        if len(MAP) < y+1 or len(MAP[y]) < x+1:
            continue
        if MAP[y][x] > threshold:
            continue

        out.append((x,y))

    return out

with open('input') as f:
    for y, line in enumerate(f):
        row = []
        for x, byte in enumerate(line.rstrip()):
            DISTANCES[(x,y)] = math.inf
            if byte == 'S':
                byte = 'a'
                START = (x,y)
                DISTANCES[START] = 0
            elif byte == 'E':
                byte = 'z'
                END = (x,y)
            row.append(ord(byte) - ord('a'))
        MAP.append(row)


visited = set([])
queue = [START]

while len(queue) > 0:
    pos = queue.pop(0)
    visited.add(pos)

    for neighbour in possible(*pos):
        if neighbour == END:
            print(DISTANCES[pos] + 1)
            quit()

        if DISTANCES[neighbour] > DISTANCES[pos] + 1:
            DISTANCES[neighbour] = DISTANCES[pos] + 1

        if neighbour not in visited and neighbour not in queue:
            queue.append(neighbour)

print("Couldn't find it!")