#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 c = ch[i][j];
                        if (c == '.')
                                continue;
                        else if (c == '^' && i > 0 && ch[i - 1][j] != '.' && ch[i - 1][j] != '#')
                                g[idx(i, j)].push_back(idx(i - 1, j));
                        else if (c == 'v' && i < r - 1 && ch[i + 1][j] != '.' && ch[i + 1][j] != '#')
                                g[idx(i, j)].push_back(idx(i + 1, j));
                        else if (c == '>' && j < c - 1 && ch[i][j + 1] != '.' && ch[i][j + 1] != '#')
                                g[idx(i, j)].push_back(idx(i, j + 1));
                        else if (c == '<' && j > 0 && ch[i][j - 1] != '.' && ch[i][j - 1] != '#')
                                g[idx(i, j)].push_back(idx(i, j - 1));
                        else if (c == '#')
                                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])
                                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';
}