#include <bits/stdc++.h>
#define pb push_back
#define sz(x) (int)x.size()
#define all(x) x.begin(), x.end()
#define f first
#define s second
using namespace std;
using ll = long long;
using pii = pair <int, int>;
const int N = 500, dx[] = {0, 0, 1, -1}, dy[] = {1, -1, 0, 0};
int n, m, ans, cnt, used[N][N];
char a[N][N], was[N][N];
void dfs(int i, int j) {
	if (min(i, j) < 0 || i == n || j == m || a[i][j] == '.' || a[i][j] == '#' || was[i][j])
		return;
	was[i][j] = 1;
	
	vector <pii> cells;
	for (int _ = 0; _ < 4; ++_) {
		int ni = i + dx[_];
		int nj = j + dy[_];
		if (min(ni, nj) >= 0 && ni < n && nj < m && a[ni][nj] == '#') {
			cnt += !used[ni][nj];
			used[ni][nj]++;
		}
	}
	ans = max(ans, cnt);
	
	if (a[i][j] == '>')
		dfs(i, j + 1);
	else if (a[i][j] == '<')
		dfs(i, j - 1);
	else if (a[i][j] == '^')
		dfs(i - 1, j);
	else 
		dfs(i + 1, j);
	
	for (int _ = 0; _ < 4; ++_) {
		int ni = i + dx[_];
		int nj = j + dy[_];
		if (min(ni, nj) >= 0 && ni < n && nj < m && a[ni][nj] == '#') {
			used[ni][nj]--;
			cnt -= !used[ni][nj];
		}
	}
	
	was[i][j] = 0;
}
int main() {
	ios :: sync_with_stdio(false);
	cin.tie(nullptr);
	cin >> n >> m;
	for (int i = 0; i < n; ++i) {
		for (int j = 0; j < m; ++j) {
			cin >> a[i][j];
		}
	}
	for (int i = 0; i < n; ++i) {
		for (int j = 0; j < m; ++j) {
			if (a[i][j] == '.' || a[i][j] == '#')
				continue;
			
			dfs(i, j);
		}
	}
	cout << ans;
	return 0;
}