//Tracks in the Snow
#include <iostream>
#include <vector>
#include <deque>
#define pr pair<int, int>
#define prr pair<pr, int>
#define f first
#define s second
using namespace std;
int dx[4] = {1, -1, 0, 0};
int dy[5] = {0, 0, 1, -1};
int main() {
int height, width;
cin >> height >> width;
vector<vector<int> > map(height, vector<int> (width, 0));
for(int i = 0; i < height; i++) {
string curr;
cin >> curr;
for(int j = 0; j < width; j++) {
if(curr.substr(j, 1) == ".") map[i][j] = 0;
else if(curr.substr(j, 1) == "R") map[i][j] = 1;
else map[i][j] = 2;
//cout << curr << " ";
}
//cout << endl;
}
/*for(int i = 0; i < height; i++) {
for(int j = 0; j < width; j++) {
cout << map[i][j] << " ";
}
cout << endl;
}*/
deque<prr> q;
prr p;
p.f.f = 0;
p.f.s = 0;
p.s = map[0][0];
q.push_back(p);
int count = 0;
int track = -1;
vector<vector<bool> > visited(height, vector<bool>(width, false));
while(!q.empty()) {
prr curr = q.front();
q.pop_front();
int x = curr.f.f;
int y = curr.f.s;
int type = curr.s;
//cout << x << " " << y << " " << type << endl;
if(type != track) {
count++;
track = type;
}
for(int i = 0; i < 4; i++) {
int nextx = x + dx[i];
int nexty = y + dy[i];
if(nextx < 0 || nextx >= height) continue;
if(nexty < 0 || nexty >= width) continue;
if(visited[nextx][nexty]) continue;
visited[nextx][nexty] = true;
int nexttype = map[nextx][nexty];
if(nexttype == 0) continue;
prr n;
n.f.f = nextx;
n.f.s = nexty;
n.s = nexttype;
if(nexttype == type) {
q.push_front(n);
}
else q.push_back(n);
}
}
cout << count << endl;
}
