#pragma comment(linker, "/stack:200000000")
//#pragma GCC optimize("Ofast")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#pragma GCC optimize ("O3")
#pragma GCC target ("sse4")
#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
using namespace std;
using namespace __gnu_pbds;
template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag,tree_order_statistics_node_update>;
const double PI = 4 * atan(1);
#define sz(x) (int)(x).size()
#define ll long long
#define ld long double
#define mp make_pair
#define pb push_back
#define eb emplace_back
#define pii pair <int, int>
#define vi vector<int>
#define f first
#define s second
#define lb lower_bound
#define ub upper_bound
#define all(x) x.begin(), x.end()
#define vpi vector<pair<int, int>>
#define vpd vector<pair<double, double>>
#define pd pair<double, double>
#define f0r(i,a) for(int i=0;i<a;i++)
#define f1r(i,a,b) for(int i=a;i<b;i++)
#define trav(a, x) for (auto& a : x)
template<typename A, typename B> ostream& operator<<(ostream &cout, pair<A, B> const &p) { return cout << "(" << p.f << ", " << p.s << ")"; }
template<typename A> ostream& operator<<(ostream &cout, vector<A> const &v) {
cout << "["; for(int i = 0; i < v.size(); i++) {if (i) cout << ", "; cout << v[i];} return cout << "]";
}
void fast_io(){
ios_base::sync_with_stdio(0);
cin.tie(NULL);
cout.tie(NULL);
}
void io(string taskname){
string fin = taskname + ".in";
string fout = taskname + ".out";
const char* FIN = fin.c_str();
const char* FOUT = fout.c_str();
freopen(FIN, "r", stdin);
freopen(FOUT, "w", stdout);
fast_io();
}
const int MAX = 3005;
const int INF = 1e9;
int grid[MAX][MAX];
int good [2][MAX][MAX];
vi pre;
inline int get(int l, int r){
if(l>r) return 0;
return pre[r] - (l == 0? 0: pre[l-1]);
}
int solve(vi&a, vi&b){
int sz = sz(a);
int ret = 0;
vi dp;
f0r(i, sz) dp.eb(0);
pre.clear();
f0r(i, sz) pre.eb(0);
f0r(i, sz){
if(i == 0) pre[i] = b[i];
else pre[i] = pre[i-1] + b[i];
}
int sum = 0;
f0r(i, sz) sum += a[i];
ret = max(sum, ret);
sum = 0;
f0r(i, sz) sum += b[i];
ret = max(sum, ret);
// cout << a << " " << b << " " << pre << endl;
int mx = -INF;
f0r(i, sz){
if(i>2){
mx = max(mx, dp[i-3] - pre[i-3]);
}
if(a[i] == 0){
continue;
}
if(i>2) dp[i] = a[i] + get(0, i-3);
else dp[i] = a[i];
if(i>0){
dp[i] = max(dp[i], dp[i-1] + a[i]);
}
if(i>1){
dp[i] = max(dp[i], dp[i-2] + a[i]);
}
if(i>2){
dp[i] = max(dp[i], mx + pre[i-3] + a[i]);
}
}
f0r(i, sz){
ret = max(ret, dp[i] + get(i+1, sz-1));
}
return ret;
}
int main(){
int n, m;
cin >> n >> m;
string temporary;
getline(cin, temporary);
f0r(i, n){
string line;
getline(cin, line);
f0r(j, m){
if(line[j] == 'R') grid[i][j] = 0;
else if (line[j] == 'G') grid[i][j] = 1;
else grid[i][j] = 2;
}
}
f0r(i, n){
f0r(j, m-2){
if(grid[i][j] == 0 && grid[i][j+1] == 1 && grid[i][j+2] == 2) good[0][i][j] = 1;
}
}
f0r(i, n-2){
f0r(j, m){
if(grid[i][j] == 0 && grid[i+1][j] == 1 && grid[i+2][j] == 2) good[1][i][j] = 1;
}
}
int ans = 0;
f0r(sum, m+n-1){
vi a; //a connected to three behind inclusive
vi b; //b conected to three ahead inclusive
f0r(j, sum+1){
int x = j;
int y = sum - j;
if(x<0 || y <0 || x>= n || y>=m) continue;
a.eb(good[1][x][y]);
b.eb(good[0][x][y]);
}
reverse(all(a));
reverse(all(b));
ans += solve(a, b);
// cout << a << endl << b << endl << solve(a, b) << endl << endl;
}
cout << ans << endl;
/* int ones = 7;
vi a;
vi b;
f0r(i, ones){
a.eb(1);
b.eb(1);
}
cout << a << endl << b << endl << solve(a, b) << endl;*/
return 0;
}
