#include <bits/stdc++.h>
#define ll long long
#define pii pair<int, int>
#define pll pair<ll, ll>
#define pdd pair<double, double>
#define F first
#define S second
#define N 250005
#define all(x) x.begin(), x.end()
using namespace std;
int r, c, dfn[N], low[N], t = 0, boss[N], nscc = 0, deg[N], in[N], out[N], val[N], dp[N];
bool ins[N], vis[N];
char ch[505][505];
stack<int> st;
vector<int> g[N], G[N];
vector<pii> sight;
int idx(int x, int y){
	return x * c + y;
}
void tarjan(int p){
	dfn[p] = low[p] = ++t;
	st.push(p); ins[p] = 1;
	for (auto i : g[p]){
		if (!dfn[i]){
			tarjan(i);
			low[p] = min(low[p], low[i]);
		}
		else if (dfn[p] > dfn[i] && ins[i])
			low[p] = min(low[p], dfn[i]);
	}
	if (low[p] == dfn[p]){
		nscc++;
		for (int x = -1; x != p; st.pop()){
			x = st.top();
			ins[x] = 0;
			boss[x] = nscc;
		}
	}
}
void dfs(int p){
	in[p] = ++t;
	for (auto i : G[p])
		dfs(i);
	out[p] = ++t;
}
bool check(int x, int y){
	return x >= 0 && x < r && y >= 0 && y < c;
}
bool isac(int a, int b){
	return in[a] < in[b] && out[a] > out[b];
}
void solve(int p){
	if (vis[p])
		return;
	vis[p] = 1;
	dp[p] += val[p];
	int add = 0;
	for (auto i : G[p]){
		solve(i);
		add = max(add, dp[i]);
	}
	dp[p] += add;
}
signed main()
{
    ios::sync_with_stdio(0);
    cin.tie(0), cout.tie(0);
	cin >> r >> c;
	for (int i = 0; i < r; i++){
		for (int j = 0; j < c; j++){
			cin >> ch[i][j];
		}
	}
	for (int i = 0; i < r; i++)
		for (int j = 0; j < c; j++){
			char cc = ch[i][j];
			if (cc == '.')
				continue;
			else if (cc == '^' && i > 0 && ch[i - 1][j] != '.' && ch[i - 1][j] != '#')
				g[idx(i, j)].push_back(idx(i - 1, j));
			else if (cc == 'v' && i < r - 1 && ch[i + 1][j] != '.' && ch[i + 1][j] != '#')
				g[idx(i, j)].push_back(idx(i + 1, j));
			else if (cc == '>' && j < c - 1 && ch[i][j + 1] != '.' && ch[i][j + 1] != '#')
				g[idx(i, j)].push_back(idx(i, j + 1));
			else if (cc == '<' && j > 0 && ch[i][j - 1] != '.' && ch[i][j - 1] != '#')
				g[idx(i, j)].push_back(idx(i, j - 1));
			else if (cc == '#')
				sight.emplace_back(i, j);
		}
	for (int i = 0; i < r; i++)
		for (int j = 0; j < c; j++)
			if (!dfn[idx(i, j)] && ch[i][j] != '.' && ch[i][j] != '#'){
				tarjan(idx(i, j));
			}
	for (int i = 0; i < r * c; i++){
		for (auto j : g[i])
			if (boss[i] != boss[j] && boss[i] != 0 && boss[j] != 0)
				G[boss[j]].push_back(boss[i]), deg[boss[i]]++;
	}
	t = 0;
	for (int i = 1; i <= nscc; i++)
		if (deg[i] == 0)
			dfs(i);

	for (auto [x, y]: sight){
		set<int> needin;
		vector<pii> d = {{1, 0}, {0, 1}, {-1, 0}, {0, -1}};
		for (auto [dx, dy] : d){
			if (check(x + dx, y + dy)){
				bool no = 0;
				vector<int> rem;
				for (auto j : needin){
					if (isac(boss[idx(x + dx, y + dy)], j))
						rem.push_back(j);
					if (isac(j, boss[idx(x + dx, y + dy)]))
						no = 1;
				}
				assert(!(no == 1 && rem.size() > 0));
				if (no == 1)
					continue;
				for (auto j : rem)
					needin.erase(j);
				needin.insert(boss[idx(x + dx, y + dy)]);
			}
		}
		for (auto i : needin)
			val[i]++;
	}
	for (int i = 1; i <= nscc; i++)
		solve(i);
	cout << *max_element(dp, dp + N) << '\n';
}
/*
7 6
^v#^^#
#<.#<>
.^<..#
.#v<<v
<^#>..
^v^.>>
><^.>>

*/