global d_sights
d_sights = {}

def trace(arr, n, m, i, j) :
    
    visited = set([])
    direction = {"^": (-1, 0), ">": (0, 1), "v": (1, 0), "<": (0, -1), "#": (0, 0)}
    sights = set([])
    x = i
    y = j
    while 0 <= x < n and 0 <= y < m and arr[x][y] in direction and (x, y) not in visited:
        visited.add((x, y))
        
        if (x, y) in d_sights :
            # print(i, j, x, y, sights)
            sights = sights.union(d_sights[(x, y)])
            d_sights[x, y] = sights
            return 
    
        # print(i, j, x, y, sights)
        
        if arr[x][y] == "#" :
            sights.add((x, y))
            break
        
        if x -1 >= 0 and arr[x - 1][y] == "#" and arr[x][y] != "^" :
            sights.add((x-1, y))
        if x + 1 < n and arr[x + 1][y] == "#" and arr[x][y] != "v" :
            sights.add((x+1, y))
        if y - 1 >= 0 and arr[x][y - 1] == "#" and arr[x][y] != ">" :
            sights.add((x, y-1))
        if y + 1 < m and arr[x][y + 1] == "#" and arr[x][y] != "<":
            sights.add((x, y+1))
            
        temp_x = x + direction[arr[x][y]] [0]
        temp_y = y + direction[arr[x][y]] [1]
        
        x, y = temp_x, temp_y
        
    d_sights[(i, j)] = sights
    
    return     
        
def solve(arr, n, m) :
    
    for i in range(n) :
        for j in range(m) :
            trace(arr, n, m, i, j)
          
    return 
            
import random

if __name__ == "__main__" :
    
    n, m = map(int, input().split())
        
    arr = []
    
    for i in range(n) :
        arr.append(list(input().strip()))
        
        
    solve(arr, n, m)
    
    # print(d_sights)
    
    mx = 0
    
    for i in d_sights:
        mx = max(mx, len(d_sights[i]))
        # print(i, d_sights[i], mx)
        
    print(mx)