#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef double ld;
#define pb push_back
#define sz(x) int(x.size())
#define all(x) x.begin(),x.end()
#define F first
#define S second
const int N = 4000;
int n, m, ans = 1, sz[N][N];
pair<int, int> p[N][N];
char c[N][N];
bool fc[N][N];
int dx[] = {1, -1, 0, 0};
int dy[] = {0, 0, 1, -1};
void dfs(int i, int j) {
fc[i][j] = true;
for (int ii = 0; ii < 4; ii++) {
int nx = i + dx[ii], ny = j + dy[ii];
if (nx >= 0 && ny >= 0 && nx < n && ny < m && c[nx][ny] == c[0][0] && !fc[nx][ny]) {
dfs(nx, ny);
}
}
}
pair<int, int> findp(int i, int j) {
return p[i][j] = (p[i][j].F == i && p[i][j].S == j ? p[i][j] : findp(p[i][j].F, p[i][j].S));
}
void merge(int i, int j, int x, int y) {
pair<int, int> f = findp(i, j), s = findp(x, y);
if (f == s)return;
if (sz[s.F][s.S] > sz[f.F][f.S])swap(f, s);
p[s.F][s.S] = f;
}
int main () {
ios::sync_with_stdio(false);
cin.tie(nullptr);
cin >> n >> m;
for (int i = 0; i < n; i++) {
for (int j = 0; j < m; j++) {
cin >> c[i][j];
p[i][j] = {i, j};
sz[i][j] = 1;
}
}
dfs(0, 0);
for (int i = 0; i < n; i++) {
for (int j = 0; j < m; j++) {
if (c[i][j] == '.')continue;
for (int k = 0; k < 4; k++) {
int nx = i + dx[k], ny = j + dy[k];
if (nx < 0 || ny < 0 || nx >= n || ny >= m)continue;
if (c[nx][ny] == c[i][j] || fc[nx][ny]) {
merge(i, j, nx, ny);
}
}
}
}
for (int i = 0; i < n; i++) {
for (int j = 0; j < m; j++) {
if (c[i][j] == '.')continue;
if (p[i][j].F == i && p[i][j].S == j) {
ans++;
}
}
}
cout << ans-1;
}
