#include <bits/stdc++.h>
#include <vector>
#include <tuple>
// #include "debugging.h"
// #include <atcoder/lazysegtree>
// #include <atcoder/modint>
// #include <atcoder/dsu>
// #include <atcoder/segtree>
// using namespace atcoder;
// using mint = modint998244353;
using namespace std;
const int LARGE = 1e9;
#define all(x) (x).begin(), (x).end()
using ll = long long;
typedef pair<ll, ll> pi;
// bool cmp(pair<ll, ll> a, pair<ll, ll> b)
// {
// if (a.second < b.second)
// return true;
// return false;
// }
// struct node
// {
// // part which will store data
// int data;
// // pointer to the previous node
// struct node *prev;
// // pointer to the next node
// struct node *next;
// };
const int MOD = 1e9+7;
template<int MOD, int RT> struct mint {
static const int mod = MOD;
static constexpr mint rt() { return RT; } // primitive root
int v;
explicit operator int() const { return v; }
mint():v(0) {}
mint(ll _v):v(int(_v%MOD)) { v += (v<0)*MOD; }
mint& operator+=(mint o) {
if ((v += o.v) >= MOD) v -= MOD;
return *this; }
mint& operator-=(mint o) {
if ((v -= o.v) < 0) v += MOD;
return *this; }
mint& operator*=(mint o) {
v = int((ll)v*o.v%MOD); return *this; }
friend mint pow(mint a, ll p) { assert(p >= 0);
return p==0?1:pow(a*a,p/2)*(p&1?a:1); }
friend mint inv(mint a) { assert(a.v != 0); return pow(a,MOD-2); }
friend mint operator+(mint a, mint b) { return a += b; }
friend mint operator-(mint a, mint b) { return a -= b; }
friend mint operator*(mint a, mint b) { return a *= b; }
};
using mi = mint<(int)MOD, 5>;
mt19937_64 RNG(chrono::steady_clock::now().time_since_epoch().count());
ll solve()
{
ll H, W; cin >> H >> W;
vector<string> A(H);
for (int i = 0; i < H; i++) cin >> A[i];
vector<vector<ll>> vis(H, vector<ll>(W));
vis[0][0] = 1;
char curr = A[0][0];
deque<pair<ll,ll>> dq;
dq.push_front(make_pair(0,0));
vector<pair<ll,ll>> ut1 = {{0, 1}, {0, -1}, {1, 0}, {-1, 0},};
ll ans = 1;
while(!dq.empty()) {
pair<ll,ll> temp = dq.front();
dq.pop_front();
ll i = temp.first, j = temp.second;
if (A[i][j] != curr) {
curr = A[i][j];
ans++;
}
for (pair<ll,ll> utp : ut1) {
ll newI = utp.first+i, newJ = utp.second+j;
if (newI < 0 || newI >= H || newJ < 0 || newJ >= W || vis[newI][newJ] || A[newI][newJ] == '.') continue;
vis[newI][newJ] = 1;
if (A[newI][newJ] == curr) dq.push_front(make_pair(newI, newJ));
else dq.push_back(make_pair(newI, newJ));
}
}
cout << ans << '\n';
return 0;
}
int main()
{
ios::sync_with_stdio(false);
cin.tie(nullptr);
// freopen("248.in", "r", stdin);
// freopen("248.out", "w", stdout);
// ll caseCnt = 1;
// ll T;
// cin >> T;
// while (T--)
// {
solve();
// cout << "Case #"<< caseCnt << ": " << ans << '\n';
// caseCnt++;
// }
return 0;
}
