//I love ManchesterUnited
#include<bits/stdc++.h>
using namespace std;
#define love ManchesterUnited
#define int long long
#define pb push_back
#define FOR(i,a,b) for (int i=(a); i<=(b); i++)
#define FORD(i,b,a) for (int i=(b); i>=(a); i--)
#define REP(i, n) for(int i=0; i<(n); ++i)
#define RED(i, n) for(int i=(n)-1; i>=0; --i)
#define time() cerr << endl << "-------------Time:" << 1000.0 * clock() / CLOCKS_PER_SEC << "ms.";
#define ALL(a) (a).begin(),(a).end()
#define cout cerr
#define ii pair<int,int>
#define iii pair<int,ii>
#define fi first
#define se second
#define endl '\n'
#define MASK(x) (1 << (x))
#define BIT(mask,i) ((mask >> i) & 1)
typedef long long ll;
template<class X, class Y>
bool minimize(X &x, const Y &y) {
if (x > y) {
x = y;
return true;
} else return false;
}
template<class X, class Y>
bool maximize(X &x, const Y &y) {
if (x < y) {
x = y;
return true;
} else return false;
}
template<class T>
T Abs(const T &x) {
return (x < 0 ? -x : x);
}
//___________________________________________________________________________________________________________________________________________________________
// CODE:
const int N = 3005;
const int MOD = 1e9 + 7;
const int INF = 1e18;
int n,m;
char a[N][N];
int dp[N][N][3];
bool can(int i,int j,int c){
if (i >= 1 && j >= 1 && i <= n && j <= m && a[i][j] == c) return true;
return false;
}
int f(int x,int y,int type){
if (x > n || y > m || x < 1 || y < 1) return 0;
int &res = dp[x][y][type];
if (res != -1) return res;
int add = 0;
if (type == 1 && can(x - 2,y,'R') && can(x - 1,y,'G') && can(x,y,'W'))
add = 1;
if (type == 2 && can(x,y - 2,'R') && can(x,y - 2,'G') && can(x,y,'W'))
add = 1;
if (type != 0 && add == 0) return 0;
res = 0;
REP(i,3){
if (type + i == 3) continue;
res = max(res,f(x - 1,y + 1,i) + add);
}
return res;
}
int32_t main()
{
// freopen("test.inp","r",stdin);
// freopen("test.out","w",stdout);
ios::sync_with_stdio(false);
cin.tie(nullptr);
cin >> n >> m;
memset(dp,-1,sizeof dp);
FOR(i,1,n) FOR(j,1,m) cin >> a[i][j];
int ans = 0;
FOR(i,1,n) ans += max({f(i,1,0), f(i,1,1), f(i,1,2)});
FOR(i,2,m) ans += max({f(n,i,0), f(n,i,1), f(n,i,2)});
cout << ans << endl;
}
