#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int MX = 3005;
int N, M;
char c[MX][MX];
int h[MX][MX], v[MX][MX];
vector<int> g[MX * MX];
int col[MX * MX];
int w = 0, b = 0;
void dfs(int v) {
if(col[v]) b++;
else w++;
for(auto u : g[v]) {
if(col[u] == 2) {
col[u] = col[v] ^ 1;
dfs(u);
} else {
assert(col[u] == (col[v] ^ 1));
}
}
}
int main() {
cin.tie(0); ios_base::sync_with_stdio(0);
for(int i = 0; i < MX * MX; i++) col[i] = 2;
cin >> N >> M;
for(int i = 0; i < N; i++) {
for(int j = 0; j < M; j++) {
cin >> c[i][j];
}
}
// build hori
int cnt = 0;
for(int i = 0; i < N; i++) {
for(int j = 0; j + 2 < M; j++) {
if(c[i][j] == 'R' && c[i][j + 1] == 'G' && c[i][j + 2] == 'W') {
cnt++;
h[i][j] = h[i][j + 1] = h[i][j + 2] = cnt;
}
}
}
// build vert
for(int j = 0; j < M; j++) {
for(int i = 0; i + 2 < N; i++) {
if(c[i][j] == 'R' && c[i + 1][j] == 'G' && c[i + 2][j] == 'W') {
cnt++;
v[i][j] = v[i + 1][j] = v[i + 2][j] = cnt;
}
}
}
for(int i = 0; i < N; i++) {
for(int j = 0; j < M; j++) {
if(h[i][j] && v[i][j]) {
g[h[i][j]].push_back(v[i][j]);
g[v[i][j]].push_back(h[i][j]);
}
}
}
// traverse graph
int ans = 0;
for(int i = 1; i <= cnt; i++) {
if(col[i] == 2) {
col[i] = 0;
w = 0, b = 0;
dfs(i);
ans += max(w, b);
}
}
cout << ans << '\n';
}
