#include <vector>
#include <list>
#include <map>
#include <set>
#include <deque>
#include <stack>
#include <queue>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <string>
#include <cstring>
#include <ctime>

using namespace std;

typedef long long ll;
typedef unsigned long long ull;

static const double EPS = 1e-8;
static const double PI = 4.0 * atan(1.0);
static const double PI2 = 8.0 * atan(1.0);

#define REP(i,n)	for(int i=0;i<(int)n;++i)
#define ALL(c)		(c).begin(),(c).end()
#define CLEAR(v)	memset(v,0,sizeof(v))
#define MP(a,b)		make_pair((a),(b))
#define ABS(a)		((a)>0?(a):-(a))
#define FOR(i,s,n)	for(int i=s;i<(int)n;++i)

int W, H;
char C[20][20];

void fill(int x, int y, char c) {
	if (x < 0 || y < 0 || x >= W || y >= H) return;
	if (C[x][y] != '.') return;
	C[x][y] = c;
	fill(x + 1, y, c);
	fill(x, y - 1, c);
	fill(x - 1, y, c);
	fill(x, y + 1, c);
}

int main(int argc, char **argv) {
	cin >> W >> H;
	REP(y, H) REP(x, W) cin >> C[x][y];
	char c = 'a';
	REP(y, H) REP(x, W) {
		if (C[x][y] == '.') {
			fill(x, y, c);
			++c;
		}
	}
	int res = W * H;
	REP(y1, H) REP(x1, W) if (C[x1][y1] == 'a') {
		REP(y2, H) REP(x2, W) if (C[x2][y2] == 'b') {
			res = min(res, abs(x2 - x1) + abs(y2 - y1) - 1);
		}
	}
	cout << res << endl;
	return 0;
}