#include <bits/stdc++.h>
#define int long long
using namespace std;
const int MAXN = 3000;
char couleur[MAXN][MAXN];
int maxPossible[2*MAXN+1][2][2];
signed main(void)
{
ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
int nbLig, nbCol;
cin >> nbLig >> nbCol;
for (int iLig(0); iLig < nbLig; ++iLig)
for (int iCol(0); iCol < nbCol; ++iCol)
cin >> couleur[iLig][iCol];
int rep(0);
for (int iDiag(0); iDiag < nbLig + nbCol; ++iDiag)
{
// iLig + iCol = iDiag
for (int i(0); i <= iDiag; ++i)
for (int j(0); j < 2; ++j)
for (int k(0); k < 2; ++k)
maxPossible[i][j][k] = 0;
int repAjout(0);
for (int iCol(nbCol-1); iCol >= 0; --iCol)
{
int iLig = iDiag - iCol;
if (iLig >= nbLig or iLig < 0)
continue;
bool djangoHoriz = false;
if (iCol + 2 < nbCol and couleur[iLig][iCol] == 'R'
and couleur[iLig][iCol+1] == 'G'
and couleur[iLig][iCol+2] == 'W')
djangoHoriz = true;
bool djangoVerti = false;
if (iLig + 2 < nbLig and couleur[iLig][iCol] == 'R'
and couleur[iLig+1][iCol] == 'G'
and couleur[iLig+2][iCol] == 'W')
djangoVerti = true;
maxPossible[iCol][0][0] =
max(djangoHoriz + maxPossible[iCol+1][0][0],
maxPossible[iCol+1][0][1]);
maxPossible[iCol][0][1] =
max(maxPossible[iCol+1][1][0], maxPossible[iCol+1][1][1]);
for (int i(0); i < 2; ++i)
for (int j(0); j < 2; ++j)
maxPossible[iCol][1][i] = max(maxPossible[iCol][1][i],
djangoVerti + maxPossible[iCol+1][i][j]);
for (int i(0); i < 2; ++i)
for (int j(0); j < 2; ++j)
repAjout = max(repAjout, maxPossible[iCol][i][j]);
}
rep += repAjout;
}
cout << rep << endl;
}
