#include <bits/stdc++.h>
#define ADD(a, b) a = (a + ll(b)) % mod
#define MUL(a, b) a = (a * ll(b)) % mod
#define MAX(a, b) a = max(a, b)
#define MIN(a, b) a = min(a, b)
#define rep(i, a, b) for(int i = int(a); i < int(b); i++)
#define rer(i, a, b) for(int i = int(a) - 1; i >= int(b); i--)
#define all(a) (a).begin(), (a).end()
#define sz(v) (int)(v).size()
#define pb push_back
#define sec second
#define fst first
#define debug(fmt, ...) Debug(__LINE__, ":", fmt, ##__VA_ARGS__)
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> pi;
typedef pair<ll, ll> pl;
typedef pair<int, pi> ppi;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<vl> mat;
typedef complex<double> comp;
void Debug() {cout << '\n'; }
template<class FIRST, class... REST>void Debug(FIRST arg, REST... rest){
	cout<<arg<<" ";Debug(rest...);}
template<class T>ostream& operator<<(ostream& out,const vector<T>& v) {
	out<<"[";if(!v.empty()){rep(i,0,sz(v)-1)out<<v[i]<<", ";out<<v.back();}out<<"]";return out;}
template<class S, class T>ostream& operator<<(ostream& out,const pair<S, T>& v){
	out<<"("<<v.first<<", "<<v.second<<")";return out;}
const int MAX_N = 200010;
const int MAX_V = 100010;
const double eps = 1e-6;
const ll mod = 1000000007;
const int inf = 1 << 29;
const ll linf = 1LL << 60;
const double PI = 3.14159265358979323846;
///////////////////////////////////////////////////////////////////////////////////////////////////

int N, M;
int X, Y;
int A[50][50];
int S[50][50];
int dp[50][50][50][50];

int get_sum(int x1, int y1, int x2, int y2) {
	return S[x2 + 1][y2 + 1] - S[x2 + 1][y1] - S[x1][y2 + 1] + S[x1][y1];
}

void solve() {
	cin >> N >> M;
	rep(i, 0, N) {
		rep(j, 0, M) {
			char c; cin >> c;
			if(c == '+') A[i][j] = 0;
			else if(c == '#') A[i][j] = 1;
			else {
				A[i][j] = 0;
				X = i; Y = j;
			}
		}
	}
	rep(i, 0, N) {
		rep(j, 0, M) {
			S[i + 1][j + 1] = A[i][j] + S[i + 1][j] + S[i][j + 1] - S[i][j];
		}
	}
	rep(x1, 0, N) {
		rep(y1, 0, M) {
			rep(x2, x1, N) {
				rep(y2, y1, M) {
					dp[x1][y1][x2][y2] = N * M;
				}
			}
		}
	}
	dp[0][0][N - 1][M - 1] = 0;
	rep(x1, 0, N) {
		rep(y1, 0, M) {
			rer(x2, N, x1) {
				rer(y2, M, y1) {
					rep(x, 0, x1 + 1) {
						rep(y, 0, y1 + 1) {
							MIN(dp[x1][y1][x2][y2], 
									dp[x][y][x2][y2] + get_sum(x, y1, x1 - 1, y2) + get_sum(x1, y, x2, y1 - 1));
						}
					}

					rep(x, x2, N) {
						rep(y, 0, y1 + 1) {
							MIN(dp[x1][y1][x2][y2],
									dp[x1][y][x][y2] + get_sum(x1, y, x2, y1 - 1) + get_sum(x2 + 1, y1, x, y2));
						}
					}

					rep(x, 0, x1 + 1) {
						rep(y, y2, M) {
							MIN(dp[x1][y1][x2][y2],
									dp[x][y1][x2][y] + get_sum(x, y1, x1 - 1, y2) + get_sum(x1, y2 + 1, x2, y));
						}
					}

					rep(x, x2, N) {
						rep(y, y2, M) {
							MIN(dp[x1][y1][x2][y2],
									dp[x1][y1][x][y] + get_sum(x2 + 1, y1, x, y2) + get_sum(x1, y2 + 1, x2, y));
						}
					}
				}
			}
		}
	}
	int ans = N * M;
	rep(x1, 0, N) {
		rep(y1, 0, M) {
			rep(x2, x1, N) {
				rep(y2, y1, M) {
					if(!(x1 <= X && X <= x2 && y1 <= Y && Y <= y2)) continue;
					MIN(ans, dp[x1][y1][x2][y2] + get_sum(x1, y1, X, Y));
					MIN(ans, dp[x1][y1][x2][y2] + get_sum(X, y1, x2, Y));
					MIN(ans, dp[x1][y1][x2][y2] + get_sum(x1, Y, X, y2));
					MIN(ans, dp[x1][y1][x2][y2] + get_sum(X, Y, x2, y2));
				}
			}
		}
	}
	cout << ans << "\n";
}

int main() {
#ifndef LOCAL
	ios::sync_with_stdio(false);
    cin.tie(0);
#endif
    cout << fixed;
	cout.precision(20);
	srand((unsigned int)time(NULL));
#ifdef LOCAL
	//freopen("in.txt", "wt", stdout); //for tester
    freopen("in.txt", "rt", stdin);
#endif	
	solve();
#ifdef LOCAL
    cerr << "Time elapsed: " << 1.0 * clock() / CLOCKS_PER_SEC << " s.\n";
#endif
	return 0;
}



Measured memory_bytes: 20480