#include <bits/stdc++.h>
using namespace std;
int n, m, cn;
vector <vector <int>> vis;
vector <vector <char>> c;
int main(){
ios::sync_with_stdio(false); cin.tie(nullptr);
cin >> n >> m;
c.resize(n+1, vector <char> (m+1));
vis.assign(n+1, vector <int> (m+1,0));
int cnt = 0;
bool tr = 0;
for(int i = 1; i <= n; i++){
for(int j = 1; j <= m; j++){
cin >> c[i][j];
}
}
int ans = 0;
queue <pair<int,int>> q, q1;
char a = c[1][1];
q.push({1,1});
while(!q.empty()){
auto [x,y] = q.front();
q.pop();
if(x > 1 and c[x-1][y] == c[x][y] and !vis[x-1][y]){
vis[x-1][y] = true;
q.push({x-1,y});
}
if(x < n and c[x+1][y] == c[x][y] and !vis[x+1][y]){
vis[x+1][y] = true;
q.push({x+1,y});
}
if(y > 1 and c[x][y-1] == c[x][y] and !vis[x][y-1]){
vis[x][y-1] = true;
q.push({x,y-1});
}
if(y < m and c[x][y+1] == c[x][y] and !vis[x][y+1]){
vis[x][y+1] = true;
q.push({x,y+1});
}
if(x > 1 and c[x-1][y] != c[x][y] and c[x-1][y] != '.' and !vis[x-1][y]){
vis[x-1][y] = true;
q1.push({x-1,y});
}
if(x < n and c[x+1][y] != c[x][y] and c[x+1][y] != '.' and !vis[x+1][y]){
vis[x+1][y] = true;
q1.push({x+1,y});
}
if(y > 1 and c[x][y-1] != c[x][y] and c[x][y-1] != '.' and !vis[x][y-1]){
vis[x][y-1] = true;
q1.push({x,y-1});
}
if(y < m and c[x][y+1] != c[x][y] and c[x][y+1] != '.' and !vis[x][y+1]){
vis[x][y+1] = true;
q1.push({x,y+1});
}
if(q.empty()){
ans++;
while(!q1.empty()){
q.push({q1.front()});
q1.pop();
}
}
}
cout << ans;
}
