#include<bits/stdc++.h>
using namespace std;
queue<pair<int,int>> q;
int h,w;
vector<vector<char>> grid;
vector<vector<bool>> vis;
void dfs(int x,int y,char z)
{
if(grid[x][y]==z)
{
vis[x][y]=1;
}
else
{
q.push({x,y});
return;
}
vector<pair<int,int>> g={{1,0},{-1,0},{0,1},{0,-1}};
for(auto [dx,dy]:g)
{
int new_x=x+dx,new_y=dy+y;
if(new_x<h && new_x>=0 && new_y<w && new_y>=0 && grid[new_x][new_y]!='.' && !vis[new_x][new_y])
{
dfs(new_x,new_y,z);
}
}
}
int main()
{
std::ios_base::sync_with_stdio(false);
std::cin.tie(nullptr);
cin>>h>>w;
grid=vector<vector<char>>(h,vector<char>(w));
vis=vector<vector<bool>>(h,vector<bool>(w,0));
for(int i=0;i<h;i++)
{
for(int j=0;j<w;j++)
{
cin>>grid[i][j];
}
}
int ans=0;
char curr='.';
q.push({0,0});
while(!q.empty())
{
auto [x,y]=q.front();
q.pop();
if(vis[x][y]==1) continue;
if(grid[x][y]!=curr)
{
ans++;
curr=grid[x][y];
}
dfs(x,y,curr);
}
cout<<ans;
}
