#include <bits/stdc++.h>
using namespace std;
#define ll long long
int tt, tc;

void solve() {
    int h, w;
	cin >> h >> w;
	vector<string> v(h);
	for (auto& u : v) cin >> u;

	vector<char> imp = { 'W', 'A', 'L', 'D', 'O' };

	vector<vector<vector<int>>> nxt(5, vector<vector<int>>(h, vector<int>(w, w)));
	for (int k = 0; k < 5; k++)
		for (int i = 0; i < h; i++) 
			for (int j = w - 2; j >= 0; --j) nxt[k][i][j] = (v[i][j + 1] == imp[k] ? j + 1 : nxt[k][i][j + 1]); 

	auto find_height = [&](int row, int col, int k) {
		if (v[row][col] == imp[k]) return 1LL;
		if (nxt[k][row][col] == w) return (ll)1e15;
		return nxt[k][row][col] - col + 1LL;
	};
	
	int sq = sqrt(h * w) + 5;
	ll ans = 1e18;
	for (int col = 0; col < w; col++) {
		for (int len = 1; len <= min(h, sq); len++) {
			vector<set<pair<ll, int>>> x(5);
			for (int k = 0; k < 5; k++) 
				for (int row = 0; row < len; row++) 
					x[k].emplace(find_height(row, col, k), row);
			auto find_min = [&]() {
				ll mx = -1e18;
				for (int k = 0; k < 5; k++) mx = max(mx, x[k].begin()->first);
				return mx;
			};
			ans = min(ans, len * find_min());
			for (int row = len; row < h; row++) {
				for (int k = 0; k < 5; k++) x[k].erase(make_pair(find_height(row - len, col, k), row - len));
				for (int k = 0; k < 5; k++) x[k].emplace(find_height(row, col, k), row);
				ans = min(ans, len * find_min());
			}
		}
	}

	cout << (ans <= h * w ? ans : -1) << "\n";
}

int main() {
    ios::sync_with_stdio(0); cin.tie(0);
    tt = 1, tc = 1; // cin >> tt;
    while (tt--) solve(), tc++;
}