#include "bits/stdc++.h"
using namespace std;
const int MAXN = 4001;
const int dx[] = {1, 0, -1, 0}, dy[] = {0, 1, 0, -1};
int n, m;
char ar[MAXN][MAXN];
bool vis[MAXN][MAXN];
char cur;
queue<pair<int, int>> qcur;
queue<pair<int, int>> qnext;
void dfs(queue<pair<int, int>> q) {
while (!q.empty()) {
pair<int, int> v = q.front();
q.pop();
if (vis[v.first][v.second]) continue;
vis[v.first][v.second] = true;
for (int i = 0; i < 4; i++) {
pair<int, int> u = {v.first + dx[i], v.second + dy[i]};
if (u.first < 0 || u.second < 0 || u.first >= n || u.second >= m) continue;
if (ar[u.first][u.second] == '.') continue;
if (vis[u.first][u.second]) continue;
if (ar[u.first][u.second] == cur)
q.push(u);
else
qnext.push(u);
}
}
}
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
cin >> n >> m;
for (int i = 0; i < n; i++)
for (int j = 0; j < m; j++)
cin >> ar[i][j];
int ans = 0;
qcur.push({0, 0});
cur = ar[0][0];
while (!qcur.empty()) {
queue<pair<int, int>> qtmp = qnext;
while (!qnext.empty()) qnext.pop();
cur = ar[qcur.front().first][qcur.front().second];
dfs(qcur);
qcur = qnext;
ans++;
}
cout << ans << '\n';
}
