#include <bits/stdc++.h>
using namespace std;
#define int long long
#define pii pair<long long, long long>
struct Stick {
int x, y;
bool r;
vector<pii> pos;
Stick(int x, int y, bool r) {
this->x = x;
this->y = y;
this->r = r;
if (r) {
pos.push_back({x, y});
pos.push_back({x, y + 1});
pos.push_back({x, y + 2});
} else {
pos.push_back({x, y});
pos.push_back({x + 1, y});
pos.push_back({x + 2, y});
}
}
bool operator&(const Stick &s) const {
for (int i = 0; i < 3; i++) {
for (int j = 0; j < 3; j++) {
if (pos[i] == s.pos[j]) return 1;
}
}
return 0;
}
};
int solve(int n, vector<Stick> &a, int took, vector<bool> &was) {
if (took == n) return 0;
bool good = 1;
for (int i = 0; i < took; i++) {
if (was[i] && (a[i] & a[took])) {
good = 0;
}
}
was[took] = 0;
int ans = solve(n, a, took + 1, was);
if (good) {
was[took] = 1;
ans = max(ans, solve(n, a, took + 1, was) + 1);
}
return ans;
}
signed main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
int n, m;
cin >> n >> m;
vector<vector<char>> a(n, vector<char>(m));
for (int i = 0; i < n; i++) {
for (int j = 0; j < m; j++) {
cin >> a[i][j];
}
}
vector<Stick> cand;
for (int i = 0; i < n - 2; i++) {
for (int j = 0; j < m; j++) {
if (a[i][j] == 'R' && a[i + 1][j] == 'G' && a[i + 2][j] == 'W') cand.push_back(Stick(i, j, 0));
}
}
for (int i = 0; i < n; i++) {
for (int j = 0; j < m - 2; j++) {
if (a[i][j] == 'R' && a[i][j + 1] == 'G' && a[i][j + 2] == 'W') cand.push_back(Stick(i, j, 1));
}
}
vector<bool> was(cand.size());
cout << solve(cand.size(), cand, 0, was) << "\n";
}
