#include <bits/stdc++.h>
#define fi first
#define se second
#define pb push_back
#define sz(a) (int)a.size()
#define all(a) a.begin(),a.end()
#define rep(i,n) for(int i=0;i<n;i++)
#define crep(i,x,n) for(int i=x;i<n;i++)
#define drep(i,n) for(int i=n-1;i>=0;i--)
#define vec(...) vector<__VA_ARGS__>
#define _3cSpNGp ios_base::sync_with_stdio(false),cin.tie(0),cout.tie(0)
using namespace std;
typedef long long ll;
typedef long double ld;
using pii=pair<int,int>;
using vi=vector<int>;
const int di[]={1,-1,0,0};
const int dj[]={0,0,1,-1};
int main(){
_3cSpNGp;
int h,w;
cin>>h>>w;
vec(vec(char)) a(h,vec(char)(w));
rep(i,h)rep(j,w){
cin>>a[i][j];
}
vec(vi) color(h,vi(w,-1));
int tm=0;
std::map<char,int> mp;
auto ok=[&](int x,int y)->bool{
return !(min(x,y)<0 or x>=h or y>=w);
};
auto dfs=[&](auto self,int i,int j)->void{
rep(dir,4){
int nei=i+di[dir],nej=j+dj[dir];
if(ok(nei,nej) and color[nei][nej]==-1 and a[nei][nej]==a[i][j]){
color[nei][nej]=color[i][j];
self(self,nei,nej);
}
}
};
rep(i,h){
rep(j,w){
if(a[i][j]!='*' and color[i][j]==-1){
// cout<<i<<" "<<j<<"\n";
char ch=a[i][j];
int cur=0;
if(mp.find(ch)==mp.end()){
cur=tm++;
}else{
bool pok=0;
rep(dir,4){
int nei=i+di[dir],nej=j+dj[dir];
if(ok(nei,nej)
and color[nei][nej]!=-1
and a[nei][nej]!='*'
and mp[ch]>color[nei][nej]){
pok=1;
}
}
if(pok) cur=mp[ch];
else cur=tm++;
}
color[i][j]=cur;
mp[ch]=cur;
dfs(dfs,i,j);
// exit(0);
}
}
}
cout<<tm<<"\n";
//
return 0;
}
