///
/// You fell for it, fool!
/// Thunder Cross Split Attack!
///
#include <bits/stdc++.h>
#define Loop(x,l,r) for(ll x = ll(l); x < ll(r); ++x)
typedef long long ll;
typedef std::pair<int,int> pii;
using namespace std;
const int N = 3009;
int ch, cv;
char a[N][N];
int n, m;
int mch[N*N];
pair<int,int> par[N*N];
bitset<N*N> vis;
vector<int> dard;
bool gdh(int i, int j){return 0 <= i && i < n && 0 <= j && j+3 <= m && a[i][j] == 'R' && a[i][j+1] == 'G' && a[i][j+2] == 'W';}
bool gdv(int i, int j){return 0 <= i && i+2 <= n && 0 <= j && j < m && a[i][j] == 'R' && a[i+1][j] == 'G' && a[i+2][j] == 'W';}
bool bfs(int s)
{
par[s] = {-1, -1};
vector<int> q;
q.push_back(s); vis[s] = 1;
for(int i = 0; i < q.size(); ++i)
{
auto v = q[i];
Loop(i,0,3)
{
if(!gdv(v/N-i,v%N+i)) continue;
int u = v-i*(N-1);
if(mch[u] == -1){
while(v != -1){
mch[u] = v;
u = par[v].second;
v = par[v].first;
}
for(int z : q) vis[z] = 0;
return 1;
}
if(vis[mch[u]]) continue;
q.push_back(mch[u]);
vis[mch[u]] = 1;
par[mch[u]] = {v, u};
}
}
return 0;
}
int main()
{
ios::sync_with_stdio(false); cin.tie(0);
cin >> n >> m;
Loop(i,0,n) cin >> a[i];
int ans = 0;
Loop(i,0,n) Loop(j,0,m) {
if(gdh(i,j)) dard.push_back(N*i+j);
if(gdv(i,j)) ++ans;
}
ans += dard.size();
srand(time(0));
random_shuffle(dard.begin(), dard.end());
memset(mch, -1, sizeof mch);
for(int v : dard)
{
ans -= bfs(v);
}
cout << ans << '\n';
}
