#include <bits/stdc++.h>
#define fst first
#define snd second
#define pb push_back
#define SZ(x) (int)x.size()
#define ALL(x) x.begin(),x.end()
#define forn(i,a,b) for(int i = a; i<b; i++)
#define mset(a,v) memset(a,v,sizeof(a))
#define FIN ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
using namespace std;
typedef long long ll;
string o = "RGW";
int main(){
ll n,m; cin>>n>>m;
vector<string> s(n); forn(i,0,n) cin>>s[i];
vector<pair<ll,ll>> ver;
vector<pair<ll,ll>> hor;
forn(i,0,n){
forn(j,0,m){
bool vert = true;
bool hori = true;
forn(h,0,3){
if(i+h>=n || s[i+h][j]!=o[h]) vert=false;
if(j+h>=m || s[i][j+h]!=o[h]) hori=false;
}
if(vert) ver.pb({i,j}) ;//, cout<<"vert "<<i<<" "<<j<<'\n';
if(hori) hor.pb({i,j}) ;//, cout<<"hori "<<i<<" "<<j<<'\n';
}
}
set<pair<ll,ll>> colv[n+5][m+5];
set<pair<ll,ll>> colh[n+5][m+5];
//cout<<"precalculos listos\n";
set<pair<ll,pair<ll,ll>>> opc;
forn(i,0,SZ(ver)){
ll cnt = 0;
ll j1=lower_bound(ALL(hor),ver[i])-hor.begin();
if(j1!=SZ(hor) && hor[j1]==ver[i]){
cnt++;
colv[ver[i].fst][ver[i].snd].insert({ver[i]});
}
ll j2=lower_bound(ALL(hor),pair<ll,ll>{ver[i].fst+1,ver[i].snd-1}) - hor.begin();
if(j2!=SZ(hor) && hor[j2]==pair<ll,ll>{ver[i].fst+1,ver[i].snd-1}){
cnt++;
colv[ver[i].fst][ver[i].snd].insert(pair<ll,ll>{ver[i].fst+1,ver[i].snd-1});
}
ll j3=lower_bound(ALL(hor),pair<ll,ll>{ver[i].fst+2,ver[i].snd-2}) - hor.begin();
if(j3!=SZ(hor) && hor[j3]==pair<ll,ll>{ver[i].fst+2,ver[i].snd-2}){
cnt++;
colv[ver[i].fst][ver[i].snd].insert(pair<ll,ll>{ver[i].fst+2,ver[i].snd-2});
}
opc.insert({cnt,{0,i}});
}
//cout<<"intersecciones verticales listas\n";
forn(i,0,SZ(hor)){
ll cnt = 0;
ll j1=lower_bound(ALL(ver),hor[i])-ver.begin();
if(j1!=SZ(ver) && ver[j1]==hor[i]){
cnt++;
colh[hor[i].fst][hor[i].snd].insert(hor[i]);
}
ll j2=lower_bound(ALL(ver),pair<ll,ll>{hor[i].fst-1,hor[i].snd+1}) - ver.begin();
if(j2!=SZ(ver) && ver[j2]==pair<ll,ll>{hor[i].fst-1,hor[i].snd+1}){
cnt++;
colh[hor[i].fst][hor[i].snd].insert(pair<ll,ll>{hor[i].fst-1,hor[i].snd+1});
}
ll j3=lower_bound(ALL(ver),pair<ll,ll>{hor[i].fst-2,hor[i].snd+2}) - ver.begin();
if(j3!=SZ(ver) && ver[j3]==pair<ll,ll>{hor[i].fst-2,hor[i].snd+2}){
cnt++;
colh[hor[i].fst][hor[i].snd].insert(pair<ll,ll>{hor[i].fst-2,hor[i].snd+2});
}
opc.insert({cnt,{1,i}});
}
//cout<<"intersecciones horizontales listas\n";
ll res = 0;
while(true){
if(SZ(opc)==0) break;
res++;
pair<ll,pair<ll,ll>> best = *opc.begin();
opc.erase(opc.begin());
//cout<<best.fst<<" "<<best.snd.fst<<" "<<best.snd.snd<<'\n';
if(best.snd.fst==0){
ll i=ver[best.snd.snd].fst;
ll j=ver[best.snd.snd].snd;
for(auto [ni,nj] : colv[i][j]){
ll ind = lower_bound(ALL(hor),pair<ll,ll>{ni,nj})-hor.begin();
colh[ni][nj].erase(colh[ni][nj].find({i,j}));
opc.erase(opc.find({SZ(colh[ni][nj]),{1,ind}}));
for(auto [nni,nnj] : colh[ni][nj]){
if(nni==i && nnj==j) continue;
ll nind = lower_bound(ALL(ver),pair<ll,ll>{nni,nnj})-ver.begin();
opc.erase(opc.find({SZ(colv[nni][nnj]),{0,nind}}));
colv[nni][nnj].erase(colv[nni][nnj].find({ni,nj}));
opc.insert({SZ(colv[nni][nnj]),{0,nind}});
}
while(!colh[ni][nj].empty()) colh[ni][nj].erase(colh[ni][nj].begin());
}
while(!colv[i][j].empty()) colv[i][j].erase(colv[i][j].begin());
}else{
ll i=hor[best.snd.snd].fst;
ll j=hor[best.snd.snd].snd;
for(auto [ni,nj] : colh[i][j]){
ll ind = lower_bound(ALL(ver),pair<ll,ll>{ni,nj})-ver.begin();
opc.erase(opc.find({SZ(colv[ni][nj]),{0,ind}}));
for(auto [nni,nnj] : colv[ni][nj]){
if(nni==i && nnj == j) continue;
ll nind = lower_bound(ALL(hor),pair<ll,ll>{nni,nnj})-hor.begin();
opc.erase(opc.find({SZ(colh[nni][nnj]),{1,nind}}));
colh[nni][nnj].erase(colh[nni][nnj].find({ni,nj}));
opc.insert({SZ(colh[nni][nnj]),{1,nind}});
}
while(!colv[ni][nj].empty()) colv[ni][nj].erase(colv[ni][nj].begin());
}
while(!colh[i][j].empty()) colh[i][j].erase(colh[i][j].begin());
}
}
cout<<res<<'\n';
return 0;
}
