import sys
input = sys.stdin
map = []
for line in input:
    map.append(list(line.strip()))

# construct a graph
for i,c in enumerate(map[0]):
    if c == '.':
        start = (i,0)
        break

def neighbors(x,y):
    n = []
    c = map[y][x]
    for i,j in [(y-1,x),(y+1,x),(y,x-1),(y,x+1)]:
        if 0 <= i < len(map) and 0 <= j < len(map[i]):
            if map[i][j] != '#':
                n.append((j,i))
    return n

spots = []
for i in range(len(map)):
    for j in range(len(map[i])):
        if map[i][j] in '.<>v^':
            n = neighbors(j,i)
            if len(n) not in (0,2):
                spots.append((j,i))

def reachable(start,spots):
    q = [(0,start)]
    dist = {}
    r = []
    while q:
        q.sort()
        n,(x,y) = q.pop(0)
        if (x,y) in dist:
            continue
        #print(x,y,neighbors(x,y))
        if (x,y) in spots and (x,y) != start:
            r.append((n,(x,y)))
        else:
            dist[x,y] = n
            for j,i in neighbors(x,y):
                if (j,i) not in dist:
                    q.append((n+1,(j,i)))

    return r

G = {}
for p in spots:
    G[p] = reachable(p,spots)

from pprint import pprint
pprint(G)

for p in G:
    if p[1] == len(map)-1:
        goal = p

print("start=",start)
print("goal=",goal)

print("brute force...")


def longest(p, seen, depth):
    best = -10000000
    b = []
    if p == goal:
        return  0,[]
    if p in seen:
        raise Error("alredy seen")
    seen.add(p)
    for n,q in G[p]:
        if q not in seen:
            t,path = longest(q, seen, depth+1)
            if t+n > best:
                best = t+n
                b = [q]+path
    seen.remove(p)
    return best, b

print(longest(start,set(),0))