#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; }