#include <bits/stdc++.h>
using namespace std;
#define si short int
#define pii pair<si, si>
#define fi first
#define se second
pii dir[4]={{0, 1}, {0, -1}, {1, 0}, {-1, 0}};
vector<pii> vec, tmp;
string a[4001];
si n, m;
void dfs(pii u)
{
char x=a[u.fi][u.se];
a[u.fi][u.se]='.';
for (pii i:dir)
{
pii v=u;
v.fi+=i.fi;
v.se+=i.se;
if (a[v.fi][v.se]!='.')
{
if (a[v.fi][v.se]==x)
dfs(v);
else
tmp.push_back(v);
}
}
}
int main()
{
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin >> n >> m;
for (si i=0; i<=m+1; i++)
a[0].push_back('.');
for (si i=1; i<=n; i++)
{
a[i].push_back('.');
for (si j=1; j<=m; j++)
{
char x;
cin >> x;
a[i].push_back(x);
}
a[i].push_back('.');
}
for (si i=0; i<=m+1; i++)
a[n+1].push_back('.');
int ans=0;
tmp.push_back({1, 1});
while (!tmp.empty())
{
vec=tmp;
tmp.clear();
for (pii u:vec)
dfs(u);
ans++;
}
cout << ans;
return 0;
}
