#define NDEBUG
#ifdef NDEBUG
#define dbg(TXTMSG) if constexpr (false) cerr << "lol"
#define dbgv(VARN) ((void)0)
#define dbgfor(COND) if constexpr (false) for (COND)
#else
#define _GLIBCXX_DEBUG 1
#define _GLIBCXX_DEBUG_PEDANTIC 1
#pragma GCC optimize("trapv")
#define dbg(TXTMSG) cerr << "\n" << TXTMSG
#define dbgv(VARN) cerr << "\n" << #VARN << " = "<< VARN << ", line: " << __LINE__ << "\n"
#define dbgfor(COND) for (COND)
#endif
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pll = pair<ll,ll>;
#define e0 first
#define e1 second
constexpr ll INFTY = 2e18;
ll N,M;
vector<string> D;
bool inrange(pll pos) {
return 0<=pos.e0 && pos.e0<M && 0<=pos.e1 && pos.e1<N;
}
bool canhskewer(pll pos) {
if (!inrange({pos.e0-1,pos.e1}) || !inrange({pos.e0+1,pos.e1})) return false;
return D[pos.e1][pos.e0-1]=='R' && D[pos.e1][pos.e0]=='G' && D[pos.e1][pos.e0+1]=='W';
}
bool canvskewer(pll pos) {
if (!inrange({pos.e0,pos.e1-1}) || !inrange({pos.e0,pos.e1+1})) return false;
//dbgv(D[pos.e1][pos.e0]=='G');
return D[pos.e1-1][pos.e0]=='R' && D[pos.e1][pos.e0]=='G' && D[pos.e1+1][pos.e0]=='W';
}
int main() {
cin.tie(nullptr);
ios_base::sync_with_stdio(false);
cin >> N >> M;
D.assign(N,"");
for (ll i = 0; i < N; ++i)
{
cin >> D[i];
assert(ll(D[i].size())==M);
}
vector<vector<ll>> dp_vert(N,vector<ll>(M));
vector<vector<ll>> dp_horiz(N,vector<ll>(M));
vector<vector<ll>> dp_no(N,vector<ll>(M));
dbgv(canvskewer({3,1}));
ll outp=0;
for (ll d = 0; d < (M+N-1); ++d)
{
pll pos;
if (d<M)
{
pos = {d,0};
}
else {
pos = {M-1,d-M+1};
}
dp_vert[pos.e1][pos.e0]=ll(canvskewer(pos));
dp_horiz[pos.e1][pos.e0]=ll(canhskewer(pos));
dp_no[pos.e1][pos.e0]=0;
pll oldpos = pos;
pos.e0-=1;
pos.e1+=1;
while (inrange(pos)) {
dp_no[pos.e1][pos.e0] = max({
dp_vert[oldpos.e1][oldpos.e0]
,dp_horiz[oldpos.e1][oldpos.e0]
,dp_no[oldpos.e1][oldpos.e0]
});
dp_vert[pos.e1][pos.e0] = canvskewer(pos) + max({
dp_vert[oldpos.e1][oldpos.e0]
,dp_no[oldpos.e1][oldpos.e0]
});
dp_horiz[pos.e1][pos.e0] = canhskewer(pos) + max({
dp_horiz[oldpos.e1][oldpos.e0]
,dp_no[oldpos.e1][oldpos.e0]
});
oldpos = pos;
pos.e0-=1;
pos.e1+=1;
}
outp+=max({
dp_vert[oldpos.e1][oldpos.e0]
,dp_horiz[oldpos.e1][oldpos.e0]
,dp_no[oldpos.e1][oldpos.e0]
});
dbgv(d << ":" << outp);
}
cout << outp;
}
