#include <bits/stdc++.h>
using namespace std;
#define pii pair<int, int>
#define fr first
#define se second
const int MAXT = 4e3 + 10;
char mat[MAXT][MAXT];
pii dad[MAXT][MAXT];
int tam[MAXT][MAXT];
int cR = 0, cF = 0;
int n, m;
int x[] = {-1, 0, 0, 1};
int y[] = {0, -1, 1, 0};
bool valid(int i, int j) {
return ((1 <= i) && (n >= i) && (j >= 1) && (j <= m));
}
pii find(pii x) {
if (dad[x.fr][x.se] == x) return x;
return dad[x.fr][x.se] = find(dad[x.fr][x.se]);
}
void print(pii a) {
cout << a.fr << " " << a.se << "\n";
}
void join(pii a, pii b) {
a = find(a), b = find(b);
if (a == b) return;
if (tam[a.fr][a.se] > tam[b.fr][b.se]) swap(a, b);
tam[b.fr][b.se] += tam[a.fr][a.se];
dad[a.fr][a.se] = b;
}
int32_t main() {
cin >> n >> m;
for (int i = 1; i <= n; i++) {
for (int j = 1; j <= m; j++) {
cin >> mat[i][j];
if (mat[i][j] != '.') {
tam[i][j] = 1;
dad[i][j] = {i, j};
}
}
}
for (int i = 1; i <= n; i++) {
for (int j = 1; j <= m; j++) {
if (mat[i][j] == '.') continue;
for (int k = 0; k < 4; k++) {
int a = i + x[k], b = j + y[k];
if ((!valid(a, b)) || (mat[i][j] != mat[a][b])) continue;
join({i, j}, {a, b});
}
}
}
for (int i = 1; i <= n; i++) {
for (int j = 1; j <= m; j++) {
if (mat[i][j] == '.') continue;
if (dad[i][j] != make_pair(i, j)) continue;
if (mat[i][j] == 'R') cR++;
else cF++;
}
}
cout << min(cR, cF) + 1 << "\n";
}
