#include <bits/stdc++.h>
using namespace std;
int main()
{
int h, w;
cin >> h >> w;
vector<string> grid(h);
for(string& s : grid)
cin >> s;
vector<vector<int>> visited(h, vector<int>(w, 0));
vector<pair<int, int>> dir = {
{1, 0},
{-1, 0},
{0, 1},
{0, -1}
};
// int ans = 0;
set<int> count;
for(int i = 0; i < h; i++)
{
for(int j = 0; j < w; j++)
{
if(visited[i][j] || grid[i][j] == '.')
continue;
visited[i][j] = 1;
queue<pair<int, int>> q;
count.insert(grid[i][j]);
q.push({i, j});
while(!q.empty())
{
auto [y, x] = q.front();
q.pop();
for(const auto& [dY, dX] : dir)
{
int nY = y + dY;
int nX = x + dX;
if((nY >= h)|| (nX >= w) || (nY < 0) || (nX < 0))
continue;
if(visited[nY][nX] || grid[nY][nX] == '.')
continue;
visited[nY][nX] = 1;
count.insert(grid[nY][nX]);
q.push({nY, nX});
}
}
// ans += count.size();
}
}
cout << count.size() << endl;
return 0;
}
