#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
#define fi first
#define se second
#define vi vector<int>
#define vll vector<long long>
#define pii pair<int, int>
#define pll pair<long long, long long>
#define pb push_back
#define mp make_pair
#define eb emplace_back
#define all(x) (x).begin(), (x).end()
#define sz(x) (int)(x).size()
mt19937 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
mt19937_64 rng64(chrono::high_resolution_clock::now().time_since_epoch().count());
inline int rand(int l,int r){return uniform_int_distribution<int>(l, r)(rng);}
inline ll rand(ll l,ll r){return uniform_int_distribution<ll>(l, r)(rng64);}
#ifdef DEBUG
auto&operator<<(auto&o,pair<auto,auto>p){return o<<"("<<p.first<<", "<<p.second<<")";}
auto operator<<(auto&o,auto x)->decltype(x.end(),o){o<<"{";int i=0;for(auto e:x)o<<","+!i++<<e;return o<<"}";}
#define debug(X...)cerr<<"["#X"]: ",[](auto...$){((cerr<<$<<"; "),...)<<endl;}(X)
#else
#define debug(...){}
#endif
struct custom_hash {
static uint64_t splitmix64(uint64_t x) {
x += 0x9e3779b97f4a7c15;
x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
return x ^ (x >> 31);
}
size_t operator()(uint64_t x) const {
static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
return splitmix64(x + FIXED_RANDOM);
}
};
const int MAXN = 3e3 + 7;
char tab[MAXN][MAXN];
int used[MAXN][MAXN];
int f[MAXN][MAXN][2];
int n, m;
const int MAXK = 1e7 + 7;
vi g[MAXK];
int c[MAXK];
int vis[MAXK];
int k;
int num[2];
void dfs(int v){
vis[v] = 1;
num[c[v]]++;
for(auto u : g[v]){
if(!vis[u]){
c[u] = !c[v];
dfs(u);
}else if(c[u] == c[v]){
cout << c[-n] << '\n';
exit(0);
}
}
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin >> n >> m;
for(int i = 1; i <= n; i++){
for(int j = 1; j <= m; j++){
cin >> tab[i][j];
f[i][j][0] = f[i][j][1] = -1;
}
}
k = 1;
for(int i = 1; i <= n; i++){
for(int j = 1; j <= m; j++){
if(j + 2 <= m && tab[i][j] == 'R' && tab[i][j + 1] == 'G' && tab[i][j + 2] == 'W'){
f[i][j][0] = k++;
if(i > 1 && f[i - 1][j + 1][1] != -1){
g[f[i][j][0]].pb(f[i - 1][j + 1][1]);
g[f[i - 1][j + 1][1]].pb(f[i][j][0]);
}
if(i > 2 && f[i - 2][j + 2][1] != -1){
g[f[i][j][0]].pb(f[i - 2][j + 2][1]);
g[f[i - 2][j + 2][1]].pb(f[i][j][0]);
}
}
if(i + 2 <= n && tab[i][j] == 'R' && tab[i + 1][j] == 'G' && tab[i + 2][j] == 'W'){
f[i][j][1] = k++;
if(j > 1 && f[i + 1][j - 1][0] != -1){
g[f[i][j][1]].pb(f[i + 1][j - 1][0]);
g[f[i + 1][j - 1][0]].pb(f[i][j][1]);
}
if(j > 2 && f[i + 2][j - 2][0] != -1){
g[f[i][j][1]].pb(f[i + 2][j - 2][0]);
g[f[i + 2][j - 2][0]].pb(f[i][j][1]);
}
}
if(f[i][j][0] != -1 && f[i][j][1] != -1){
g[f[i][j][0]].pb(f[i][j][1]);
g[f[i][j][1]].pb(f[i][j][0]);
}
}
}
int ans = 0;
for(int i = 1; i < k; i++){
if(!vis[i]){
num[0] = num[1] = 0;
dfs(i);
ans += max(num[0], num[1]);
}
}
cout << ans << '\n';
return 0;
}
