/**
 *    author:  MaGnsi0
 *    created: 22.04.2023 20:06:29
**/
#include <bits/stdc++.h>

using namespace std;

const int dx[4] = {-1, 0, 0, 1};
const int dy[4] = {0, -1, 1, 0};

int main() {
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    int n, m;
    cin >> n >> m;
    vector<string> a(n);
    for (int i = 0; i < n; ++i) {
        cin >> a[i];
    }
    function<vector<pair<int, int>>(int, int)> S = [&](int x, int y) {
        vector<pair<int, int>> ans;
        for (int i = 0; i < 4; ++i) {
            int nx = x + dx[i];
            int ny = y + dy[i];
            if (nx < 0 || nx >= n) { continue; }
            if (ny < 0 || ny >= m) { continue; }
            if (a[nx][ny] == '#') {
                ans.emplace_back(nx, ny);
            }
        }
        return ans;
        return ans;
    };
    int ans = 0;
    set<pair<int, int>> s;
    vector<vector<bool>> visited(n, vector<bool>(m, false));
    function<void(int, int)> dfs = [&](int x, int y) {
        if (x < 0 || x >= n) {
            return;
        }
        if (y < 0 || y >= m) {
            return;
        }
        if (a[x][y] == '.' || a[x][y] == '#') {
            return;
        }
        if (visited[x][y]) {
            return;
        }
        visited[x][y] = true;
        for (auto& p : S(x, y)) {
            s.insert(p);
        }
        if (a[x][y] == '>') {
            dfs(x, y + 1);
        } else if (a[x][y] == 'v') {
            dfs(x + 1, y);
        } else if (a[x][y] == '<') {
            dfs(x, y - 1);
        } else {
            dfs(x - 1, y);
        }
    };
    for (int i = 0; i < n; ++i) {
        for (int j = 0; j < m; ++j) {
            if (a[i][j] != '.' && a[i][j] != '#') {
                s.clear();
                visited = vector<vector<bool>>(n, vector<bool>(m, false));
                dfs(i, j);
                ans = max(ans, (int)s.size());
            }
        }
    }
    cout << ans;
}