#include <bits/stdc++.h>
using namespace std;
const int MAXN = 3 * 1000 + 10;
char tab[MAXN][MAXN];
bool peut[MAXN][MAXN][2];
// 0 -> droite
// 1 -> bas
//
int mod3(int n)
{
return ((n % 3) + 3) % 3;
}
int main()
{
ios::sync_with_stdio(false);
int N , M;
cin >> N >> M;
for (int i = 0 ; i < N ; i++)
{
for (int j = 0 ; j < M ; j++)
{
cin >> tab[i][j];
}
}
for (int i = 0 ; i < N ; i++)
{
for (int j = 0 ; j < M ; j++)
{
if (j + 2 < M && tab[i][j] == 'R' && tab[i][j + 1] == 'G' && tab[i][j + 2] == 'W')
{
peut[i][j][0] = true;
}
if (i + 2 < N && tab[i][j] == 'R' && tab[i + 1][j] == 'G' && tab[i + 2][j] == 'W')
{
peut[i][j][1] = true;
}
}
}
int sol = 0;
int i0 = 0;
int j0 = 0;
while (j0 < M && i0 < N)
{
int nb[3];
nb[0] = nb[1] = nb[2] = 0;
int ofs = 0;
int i = i0;
int j = j0;
while (i < N && j >= 0)
{
int valb = max(nb[ofs] , max(nb[mod3(ofs - 1)] , nb[mod3(ofs - 2)])) + 1;
int vald = nb[ofs] + 1;
nb[mod3(ofs - 2)] = max(nb[mod3(ofs - 2)] , nb[ofs]);
nb[mod3(ofs - 1)] = max(nb[mod3(ofs - 1)] , nb[mod3(ofs - 2)]);
if (peut[i][j][0])
{
nb[mod3(ofs - 2)] = max(nb[mod3(ofs - 2)] , vald);
nb[mod3(ofs - 1)] = max(nb[mod3(ofs - 1)] , vald);
nb[mod3(ofs - 0)] = max(nb[mod3(ofs - 0)] , vald);
}
if (peut[i][j][1])
{
nb[ofs] = valb;
}
// if (j0 == 7)
// {
// cout<<nb[ofs]<<" "<<nb[mod3(ofs - 1)]<<" "<<nb[mod3(ofs - 2)]<<endl;
// }
i++;
j--;
ofs = mod3(ofs + 1);
}
int aj = max(nb[0] , max(nb[1] , nb[2]));
sol += aj;
// cout<<aj<<endl;
j0++;
if (j0 == M)
{
i0++;
j0 = M - 1;
}
}
cout<<sol<<endl;
}
