#include <bits/stdc++.h>
using namespace std;
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
int n, m;
cin >> n >> m;
char c[n + 1][m + 1];
for (int i = 1; i <= n; i++) {
for (int j = 1; j <= m; j++) {
cin >> c[i][j];
}
}
int ans = 0;
for (int mask = 0; mask < (1 << (n * m)); mask++) {
int b[n + 1][m + 1];
for (int i = 0; i < n; i++) {
for (int j = 0; j < m; j++) {
b[i + 1][j + 1] = ((mask >> (i*m + j)) & 1);
}
}
int res = 0;
bool was[n + 1][m + 1];
for (int i = 0; i <= n; i++) {
for (int j = 0; j <= m; j++) {
was[i][j] = 0;
}
}
for (int i = 1; i <= n; i++) {
for (int j = 1; j <= m; j++) {
if (c[i][j] == 'R') {
if (b[i][j]) {
if (j + 2 <= m && c[i][j + 1] == 'G' && c[i][j + 2] == 'W' && !was[i][j + 1] && !was[i][j + 2]) {
was[i][j] = was[i][j + 1] = was[i][j + 2] = 1;
res++;
}
} else {
if (i + 2 <= n && c[i + 1][j] == 'G' && c[i + 2][j] == 'W' && !was[i + 1][j] && !was[i + 2][j]) {
was[i][j] = was[i + 1][j] = was[i + 2][j] = 1;
res++;
}
}
}
}
}
ans = max(ans, res);
}
cout << ans;
return 0;
}
