#include <bits/stdc++.h>
using namespace std;
#define int long long
mt19937_64 RNG(chrono::steady_clock::now().time_since_epoch().count());
const int N = 6e3 + 5;
int n, m, diagonals;
char a[N][N];
int dp[N][3];
bool canTake[N][N][3];
/*
1 -> up to down
2 -> left to right
*/
bool up(int i, int j) {
if(i <= 1 || i >= n) {
return false;
}
if(a[i - 1][j] != 'R' || a[i][j] != 'G' || a[i + 1][j] != 'W') {
return false;
}
return true;
}
bool left(int i, int j) {
if(j <= 1 || j >= m) {
return false;
}
if(a[i][j - 1] != 'R' || a[i][j] != 'G' || a[i][j + 1] != 'W') {
return false;
}
return true;
}
int Recur(int row, int prev) {
//cout << "Recur(" << row << ", " << prev << ")\n";
if(row > n) {
//cout << "Row already exceeded\n";
return 0;
}
if(dp[row][prev] != -1) {
//cout << "Dp already initialized = " << dp[row][prev] << "\n";
return dp[row][prev];
}
int col = diagonals - row;
int ans = Recur(row + 1, 0); //not choosing anything here :sadge:
if(prev == 0) {
//can choose both
if(canTake[row][col][1]) {
ans = max(ans, Recur(row + 1, 1) + 1);
}
if(canTake[row][col][2]) {
ans = max(ans, Recur(row + 1, 2) + 1);
}
}
else if(prev == 1) {
//can't choose left to right
if(canTake[row][col][1]) {
ans = max(ans, Recur(row + 1, 1) + 1);
}
}
else {
//can't choose up to down
if(canTake[row][col][2]) {
ans = max(ans, Recur(row + 1, 2) + 1);
}
}
return dp[row][prev] = ans;
}
void Solve() {
cin >> n >> m;
for(int i = 1; i <= n; i++) {
for(int j = 1; j <= m; j++) {
cin >> a[i][j];
}
}
for(int i = 1; i <= n; i++) {
for(int j = 1; j <= m; j++) {
canTake[i][j][0] = true;
canTake[i][j][1] = up(i, j);
canTake[i][j][2] = left(i, j);
}
}
int ans = 0;
for(diagonals = 2; diagonals <= n + m; diagonals++) {
for(int i = 0; i < N; i++) {
for(int j = 0; j < 3; j++) {
dp[i][j] = -1;
}
}
ans += Recur(1, 0); //row, previous taken...if any
/*for(int i = 1; i <= n; i++) {
for(int j = 0; j < 3; j++) {
cout << dp[i][j] << " ";
}
cout << "\n";
}*/
}
cout << ans << "\n";
}
int32_t main() {
auto begin = std::chrono::high_resolution_clock::now();
ios_base::sync_with_stdio(0);
cin.tie(0);
int t = 1;
//cin >> t;
while(t--) {
Solve();
}
auto end = std::chrono::high_resolution_clock::now();
auto elapsed = std::chrono::duration_cast<std::chrono::nanoseconds>(end - begin);
cerr << "Time measured: " << elapsed.count() * 1e-9 << " seconds.\n";
return 0;
}
