#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
template<class T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
template<class A> ostream& operator<<(ostream &cout, vector<A> const &v) {cout << "["; for(int i = 0; i < v.size(); i++) {if (i) cout << ", "; cout << v[i];} return cout << "]";};
template<class A, class B> ostream& operator<<(ostream &cout, const pair<A,B> &x) {return cout << "(" <<x.first << ", " << x.second << ")";};
template<class T> void pv(T a, T b) {cerr << "["; for (T i = a; i != b; ++i) cerr << *i << " "; cerr << "]\n";}
void _print() {cerr << "]\n";}
template<class T, class... V> void _print(T t, V... v) {cerr << t; if (sizeof...(v)) cerr << ", "; _print(v...);}
#define debug(x...) cerr << "[" << #x << "] = [", _print(x)
#define fi first
#define se second
#define SZ(x) (int)((x).size())
#define pii pair<int,int>
int n,m;
string grid[3000];
vector<vector<int>> adj;
vector<bool> ff;
vector<int> col;
int conv(int a, int b, int c) {
return a*m+b+c*n*m;
}
bool exist(int a, int b, int c) {
if (a < 0 || a >= n || b < 0 || b >= m) return false;
if (c == 0) {
if (a-1 >= 0 && a+1 < n && grid[a-1][b] == 'R' && grid[a][b] == 'G' && grid[a+1][b] == 'W') return true;
} else {
if (b-1 >= 0 && b+1 < m && grid[a][b-1] == 'R' && grid[a][b] == 'G' && grid[a][b+1] == 'W') return true;
}
return false;
}
void addedge(int a, int b) {
adj[a].push_back(b);
adj[b].push_back(a);
}
int ct[2];
void dfs(int v) {
for (int a : adj[v]) {
if (col[a] != -1) continue;
col[a] = 1-col[v];
ct[col[a]]++;
dfs(a);
}
}
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
cin >> n >> m;
for (int q = 0; q < n; q++) cin >> grid[q];
adj.resize(n*m*2+5);
ff.resize(n*m*2+5);
col.resize(n*m*2+5,-1);
for (int q = 0; q < n; q++) {
for (int w = 0; w < m; w++) {
if (exist(q,w,0)) {
int x = conv(q,w,0);
ff[x] = true;
if (exist(q-1,w+1,1)) addedge(x,conv(q-1,w+1,1));
if (exist(q,w,1)) addedge(x,conv(q,w,1));
if (exist(q+1,w-1,1)) addedge(x,conv(q+1,w-1,1));
}
if (exist(q,w,1)) ff[conv(q,w,1)] = true;
}
}
int ans = 0;
for (int q = 0; q < n*m*2+5; q++) {
if (ff[q] && col[q] == -1) {
col[q] = 0;
ct[0] = 1;
ct[1] = 0;
dfs(q);
ans += max(ct[0], ct[1]);
}
}
cout << ans << '\n';
return 0;
}
