// Source: https://usaco.guide/general/io
#include <bits/stdc++.h>
using namespace std;
int H, W;
string M[4005];
bool v[4005][4005];
int main() {
cin >> H >> W;
for (int i = 0; i < H; i++) {
cin >> M[i];
}
if (M[0][0] == '.') return 0;
deque<pair<int,int> > q;
q.push_back(make_pair(0,0));
v[0][0] = true;
int res = 1;
char current = M[0][0];
while (!q.empty()) {
auto c = q.front();
q.pop_front();
if (M[c.first][c.second] != current) {
res++;
current = M[c.first][c.second];
}
for (auto i : {-1,1}) {
for (auto j : {0,1}) {
if (j==0) {
if (((i < 0 && c.first > 0) || (i > 0 && c.first < H-1)) && !v[c.first+i][c.second] && M[c.first+i][c.second] != '.') {
v[c.first+i][c.second] = true;
if (M[c.first][c.second] == M[c.first+i][c.second]) {
q.push_front(make_pair(c.first+i,c.second));
} else {
q.push_back(make_pair(c.first+i,c.second));
}
}
} else {
if (((i < 0 && c.second > 0) || (i > 0 && c.second < W-1)) && !v[c.first][c.second+i] && M[c.first][c.second+i] != '.') {
v[c.first][c.second+i] = true;
if (M[c.first][c.second] == M[c.first][c.second+i]) {
q.push_front(make_pair(c.first,c.second+i));
} else {
q.push_back(make_pair(c.first,c.second+i));
}
}
}
}
}
}
cout << res << endl;
}
