#include <cstdio>
#include <cstdlib>
#include <stack>

using namespace std;

int R, S;
char mapa[1111][1111];
int oznaceno[1111][1111];
int ans = 0;
int dx[4] = {0, 0, 1, -1};
int dy[4] = {1, -1, 0, 0};

int jidlo(int y0, int x0) {
	int res = 0;
	stack<pair<int,int> > st;
	st.push(make_pair(y0,x0));
	while (!st.empty()) {
		int y = st.top().first;
		int x = st.top().second;
		st.pop();
		if (y>=R || y<0 || x>=S || x<0 || oznaceno[y][x]) continue;
		if (mapa[y][x]=='#' || mapa[y][x]=='J') {
			oznaceno[y][x] = 1;
			if (mapa[y][x]=='J') res++;
			for (int i=0; i<4; i++) st.push(make_pair(y+dy[i], x+dx[i]));
		}
	}
	return res;
}

// DFS = depth-first search = prohledávání do hloubky
void dfs(int y0, int x0) {
	stack<pair<int, int> > st;
	st.push(make_pair(y0,x0));
	while (!st.empty()) {
		int y = st.top().first;
		int x = st.top().second;
		st.pop();
		if (y>=R || y<0 || x>=S || x<0) continue;
		if (!oznaceno[y][x]) {
			if (mapa[y][x]=='#' || mapa[y][x]=='J') ans = max(ans, jidlo(y,x));
			else {
				oznaceno[y][x] = 1;
				for (int i=0; i<4; i++) st.push(make_pair(y+dy[i], x+dx[i]));
			}
		}
	}
}

int main() {
	int sx, sy;
	scanf("%d%d", &S, &R);
	for (int i=0; i<R; i++) for (int j=0; j<S; j++) {
		scanf(" %c", &mapa[i][j]);
		if (mapa[i][j]=='H') {
			sy = i;
			sx = j;
		}
	}
	dfs(sy, sx);
	printf("%d\n", ans);
	return 0;
}