#include <bits/stdc++.h>

using namespace std;

#define int int64_t

int dx[4] = {2, -2, 0, 0}, dy[4] = {0, 0, 2, -2};
string endpoint = "v^><";

vector<string> s;
int dp[500][500];
int a[500][500];
int n, m;

bool ok(int x, int y) {
    return 0 <= x && x < n && 0 <= y && y < m;
}

void dfs(int x, int y) {
    dp[x][y] = a[x][y];
    for (int dir = 0; dir < 4; dir++) {
        int to_x = x + dx[dir];
        int to_y = y + dy[dir];
        if (ok(to_x, to_y) && s[to_x][to_y] == endpoint[dir]) {
            dfs(to_x, to_y);
            dp[x][y] += max(0ll, dp[to_x][to_y]);
        }
    }
}

int32_t main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0); cout.tie(0);
    cin >> n >> m;
    s.resize(n);
    for (int i = 0; i < n; i++) {
        cin >> s[i];
    }
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < m; j++) {
            cin >> a[i][j];
        }
    }
    int sx = -1, sy = -1;
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < m; j++) {
            if (s[i][j] == '.') {
                sx = i;
                sy = j;
            }
        }
    }
    dfs(sx, sy);
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < m; j++) {
            cerr << dp[i][j] << ' ';
        }
    }
    cout << dp[sx][sy];
}