#include <iostream>
#include <cstdio>
#include <vector>
#include <cmath>
#include <queue>
using namespace std;
vector<int> radd = { -1, 0, 1, 0 };
vector<int> cadd = { 0, -1, 0, 1 };
int main()
{
ios::sync_with_stdio(false);
cin.tie(nullptr);
int h, w;
cin >> h >> w;
vector<vector<char>> trk(h + 2, vector<char>(w + 2, '.'));
for (int i = 1; i <= h; i++) for (int j = 1; j <= w; j++) cin >> trk[i][j];
int ans = 0;
vector<vector<bool>> vis(h + 2, vector<bool>(w + 2, false));
queue<pair<int, int>> bfs;
queue<pair<int, int>> nxt;
bfs.push({ 1, 1 });
vis[1][1] = true;
while (!bfs.empty())
{
ans++;
while (!bfs.empty())
{
int r = bfs.front().first, c = bfs.front().second;
bfs.pop();
for (int dir = 0; dir < 4; dir++) if (!vis[r + radd[dir]][c + cadd[dir]])
{
vis[r + radd[dir]][c + cadd[dir]] = true;
if (trk[r + radd[dir]][c + cadd[dir]] == trk[r][c]) bfs.push({ r + radd[dir], c + cadd[dir] });
else if (trk[r + radd[dir]][c + cadd[dir]] != '.') nxt.push({ r + radd[dir], c + cadd[dir] });
}
}
while (!nxt.empty())
{
bfs.push(nxt.front());
nxt.pop();
}
}
cout << ans;
}
