#include <bits/stdc++.h>
// #pragma GCC optimize("Ofast,no-stack-protector,unroll-loops")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
// #define int long long
#define ll long long
#define pii pair<int, int>
#define all(v) v.begin(), v.end()
using namespace std;
const int oo = 1e9 + 9;
const int MAX = 4000 + 5, LOGMAX = 20, B = 441, MOD = 998244353;
int n, m;
int vis[MAX][MAX];
vector<char> ch = {'R', 'F'};
vector<pii> dir = {{1, 0}, {-1, 0}, {0, 1}, {0, -1}};
string arr[MAX];
void solve(){
cin >> n >> m;
bool r = 0, f = 0;
for(int i = 1; i <= n; i++){
cin >> arr[i];
arr[i] = '%' + arr[i];
}
if(arr[1][1] == '.'){
cout << "0\n";
return;
}
int ans = 0;
deque<pii> q;
q.push_back({1, 1});
char pr = '$';
while(q.size()){
pii a = q.front();
q.pop_front();
if(vis[a.first][a.second]) continue;
vis[a.first][a.second] = 1;
if(arr[a.first][a.second] != pr) ans++;
pr = arr[a.first][a.second];
for(auto d : dir){
int nx = a.first + d.first;
int ny = a.second + d.second;
if(!(1 <= nx && nx <= n && 1 <= ny && ny <= m) || (arr[nx][ny] == '.')) continue;
if(arr[nx][ny] == pr) q.push_front({nx, ny});
else q.push_back({nx, ny});
}
}
cout << ans << '\n';
}
signed main(){
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int t = 1;
// cin >> t;
while(t--) solve();
}
