#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define ld double
#define sz(x) (int)x.size()
#define all(x) x.begin(),x.end()
#define pb emplace_back
#define X first
#define Y second
const int N = 3005;
typedef pair<int,int> ii;
char a[N][N];
int t[N][N];
int p[N * N];
int s[N * N];
int lead(int x) {
return p[x] == x ? x : p[x] = lead(p[x]);
}
int join(int x,int y) {
x = lead(x);
y = lead(y);
if (x == y)
return 0;
if (s[x] < s[y])
swap(x,y);
p[y] = x;
s[x] += s[y];
return 1;
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
int n; cin >> n;
int m; cin >> m;
int cnt = 0;
for(int i = 0 ; i < n ; ++i)
for(int j = 0 ; j < m ; ++j) {
cin >> a[i][j];
if (a[i][j] != 'G') {
p[cnt] = cnt;
s[cnt] = 1;
t[i][j] = cnt++;
}
if (a[i][j] == 'W') {
if (i > 1 && a[i - 1][j] == 'G' && a[i - 2][j] == 'R')
join(t[i][j],t[i - 2][j]);
if (j > 1 && a[i][j - 1] == 'G' && a[i][j - 2] == 'R')
join(t[i][j],t[i][j - 2]);
}
}
int ans = 0;
for(int i = 0 ; i < cnt ; ++i) if (p[i] == i)
ans += s[i] / 2;
cout << ans << endl;
}
