#include <bits/stdc++.h>
using namespace std;
void setup()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
}
int n, m, f[3][3000], res;
string s[3000];
int main()
{
setup();
cin >> n >> m;
for (int i = 0; i < n; ++i)
{
cin >> s[i];
}
for (int k = n + m - 2; k >= 0; --k)
{
for (int v = 0; v < 3; ++v)
{
fill_n(f[v], n, 0);
}
for (int i = n - 1, j; i >= 0; --i)
{
j = k - i;
if (0 <= i && i < n && 0 <= j && j < m)
{
f[0][i] = (i == n - 1 ? 0 : max({f[0][i + 1], f[1][i + 1], f[2][i + 1]}));
if (j + 2 < m && s[i][j] == 'R' && s[i][j + 1] == 'G' && s[i][j + 2] == 'W')
{
f[1][i] = f[0][i] + 1;
}
if (i + 2 < n && s[i][j] == 'R' && s[i + 1][j] == 'G' && s[i + 2][j] == 'W')
{
f[2][i] = max({f[2][i + 1], f[0][i + 2], f[2][i + 2]}) + 1;
}
if (i == 0 || j == m - 1)
{
res += max({f[0][i], f[1][i], f[2][i]});
}
}
}
}
cout << res;
return 0;
}
