#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 int ll;
string o = "RGW";
short cnt;
set<pair<pair<short,short>,short>>::iterator jj;
set<pair<short,pair<short,pair<short,short>>>> opc;
pair<pair<short,short>,short> aux;
set<pair<pair<short,short>,short>> ver;
set<pair<pair<short,short>,short>> hor;
//sign
// 1 = vertical
// -1 = horizontal
ll col(pair<pair<short,short>,short> x,set<pair<pair<short,short>,short>> &voh, short sign){
// cout<<x.fst.fst<<" "<<x.fst.snd<<" "<<sign<<'\n';
cnt = 0;
pair<short,short> i = x.fst;
aux.snd=0;
aux.fst=i;
jj=voh.lower_bound(aux);
if(jj!=voh.end() && (*jj).fst==aux.fst){
cnt++;
}
aux.fst={i.fst+(1*sign),i.snd-(1*sign)};
jj=voh.lower_bound(aux);
if(jj!=voh.end() && (*jj).fst==aux.fst){
cnt++;
}
aux.fst={i.fst+(2*sign),i.snd-(2*sign)};
jj=voh.lower_bound(aux);
if(jj!=voh.end() && (*jj).fst==aux.fst){
cnt++;
}
// cout<<"new cnt "<<cnt<<'\n';
opc.erase(opc.find({x.snd,{sign,i}}));
opc.insert({cnt,{sign,i}});
if(sign==1){
ver.erase(ver.find(x));
ver.insert({i,cnt});
}else{
hor.erase(hor.find(x));
hor.insert({i,cnt});
}
// cout<<"return\n";
return cnt;
}
void recol(pair<pair<short,short>,short> x, set<pair<pair<short,short>,short>> &voh , short sign){
pair<short,short> i = x.fst;
aux.snd=0;
aux.fst=i;
jj=voh.lower_bound(aux);
if(jj!=voh.end() && (*jj).fst==aux.fst){
if(sign==1) col(*jj,hor,-1);
else col(*jj,ver,1);
}
aux.fst={i.fst+(1*sign),i.snd-(1*sign)};
jj=voh.lower_bound(aux);
if(jj!=voh.end() && (*jj).fst==aux.fst){
if(sign==1) col(*jj,hor,-1);
else col(*jj,ver,1);
}
aux.fst={i.fst+(2*sign),i.snd-(2*sign)};
jj=voh.lower_bound(aux);
if(jj!=voh.end() && (*jj).fst==aux.fst){
if(sign==1) col(*jj,hor,-1);
else col(*jj,ver,1);
}
}
void rem(pair<pair<short,short>,short> x, set<pair<pair<short,short>,short>> &voh , short sign){
pair<short,short> i = x.fst;
aux.snd=0;
aux.fst=i;
jj=voh.lower_bound(aux);
if(jj!=voh.end() && (*jj).fst==aux.fst){
voh.erase(jj);
opc.erase(opc.find({(*jj).snd,{sign*-1,(*jj).fst}}));
if(sign==1) recol(*jj,hor,-1);
else recol(*jj,ver,1);
}
aux.fst={i.fst+(1*sign),i.snd-(1*sign)};
jj=voh.lower_bound(aux);
if(jj!=voh.end() && (*jj).fst==aux.fst){
voh.erase(jj);
opc.erase(opc.find({(*jj).snd,{sign*-1,(*jj).fst}}));
if(sign==1) recol(*jj,hor,-1);
else recol(*jj,ver,1);
}
aux.fst={i.fst+(2*sign),i.snd-(2*sign)};
jj=voh.lower_bound(aux);
if(jj!=voh.end() && (*jj).fst==aux.fst){
voh.erase(jj);
opc.erase(opc.find({(*jj).snd,{sign*-1,(*jj).fst}}));
if(sign==1) recol(*jj,hor,-1);
else recol(*jj,ver,1);
}
}
int main(){ FIN;
ll n,m; cin>>n>>m;
vector<string> s(n); forn(i,0,n) cin>>s[i];
bool vert;
bool hori;
forn(i,0,n){
forn(j,0,m){
vert = true;
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.insert({{i,j},0}), opc.insert({0,{1,{i,j}}});//, cout<<"vert "<<i<<" "<<j<<'\n';
if(hori) hor.insert({{i,j},0}), opc.insert({0,{-1,{i,j}}});//, cout<<"hori "<<i<<" "<<j<<'\n';
}
}
// cout<<"llegamos\n";
for(auto i:ver) col(i,hor,1);
for(auto i:hor) col(i,ver,-1);
// cout<<"colisiones listas\n";
ll res = 0;
while(true){
if(SZ(opc)==0) break;
res++;
pair<short,pair<short,pair<short,short>>> best = *opc.begin();
opc.erase(opc.begin());
if(best.snd.fst==1){
ver.erase(ver.find({best.snd.snd,best.fst}));
rem({best.snd.snd,best.fst},hor,1);
}else{
hor.erase(hor.find({best.snd.snd,best.fst}));
rem({best.snd.snd,best.fst},ver,-1);
}
}
cout<<res<<'\n';
return 0;
}
