#include <bits/stdc++.h>
using namespace std;
#define int long long
const int maxn = 3e3 + 5;
char a[maxn][maxn];
int dp[2 * maxn][maxn][3];
signed main(){
ios_base::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
int n, m; cin >> n >> m;
for(int i = 0; i < n; i++){
for(int j = 0; j < m; j++) cin >> a[i][j];
}
int ans = 0;
for(int k = 0; k < n + m - 1; k++){
int id = 0;
for(int i = min(k, n - 1); 0 <= i && k - i < m; i--){
if(id > 0){
dp[k][id][0] = max({dp[k][id - 1][0], dp[k][id - 1][1], dp[k][id - 1][2]});
dp[k][id][1] = max(dp[k][id - 1][0], dp[k][id - 1][1]);
dp[k][id][2] = max(dp[k][id - 1][0], dp[k][id - 1][2]);
}
dp[k][id][1] += (i >= 1 && i + 1 < n && a[i - 1][k - i] == 'R' && a[i][k - i] == 'G' && a[i + 1][k - i] == 'W');
dp[k][id][2] += (k - i >= 1 && k - i + 1 < m && a[i][k - i - 1] == 'R'&& a[i][k - i] == 'G' && a[i][k - i + 1] == 'W');
id++;
}
ans += max({dp[k][id - 1][0], dp[k][id - 1][1], dp[k][id - 1][2]});
}
cout << ans;
}
