#include <bits/stdc++.h>
#pragma optimize("Ofast")
#pragma target("avx2")
using namespace std;
#define ll long long
#define ld long double
#define pb push_back
#define pf push_front
#define pii pair<int,int>
#define all(v) v.begin(),v.end()
#define F first
#define S second
#define mem(a,i) memset(a,i,sizeof(a))
#define sz(s) (int)s.size()
#define y1 yy
#define ppb pop_back
#define lb lower_bound
#define ub upper_bound
#define gcd(a,b) __gcd(a,b)
#define in insert
// #define int ll
const int MAX=3000+15;
const int B=2e5;
const int N=104;
const int block=450;
const int maxB=MAX/B+10;
const ll inf=1e9;
const int mod=1e9+7;
const int mod1=1e9+9;
const ld eps=1e-9;
int dx[8]={1,0,-1,0,1,-1,-1,1};
int dy[8]={0,1,0,-1,1,-1,1,-1};
int binpow(int a,int n){
if(!n)return 1;
if(n%2==1)return a*binpow(a,n-1);
int k=binpow(a,n/2);
return k*k;
}
int n,m;
int a[MAX][MAX];
int getU(int i,int j){
if(a[i][j]==0){
if(i+2>n)return -1;
if(a[i+1][j]==1&&a[i+2][j]==2)return i;
return -1;
}
if(a[i][j]==1){
if(i-1<1||i+1>n)return -1;
if(a[i-1][j]==0&&a[i+1][j]==2)return i-1;
return -1;
}
if(a[i][j]==2){
if(i-2<1)return -1;
if(a[i-2][j]==0&&a[i-1][j]==1)return i-2;
}
return -1;
}
int getL(int i,int j){
if(a[i][j]==0){
if(j+2>m)return -1;
if(a[i][j+1]==1&&a[i][j+2]==2)return j;
return -1;
}
if(a[i][j]==1){
if(j-1<1||j+1>m)return -1;
if(a[i][j-1]==0&&a[i][j+1]==2)return j-1;
return -1;
}
if(a[i][j]==2){
if(j-2<1)return -1;
if(a[i][j-2]==0&&a[i][j-1]==1)return j-2;
return -1;
}
return -1;
}
int dp[MAX][2];
void solve(){
cin>>n>>m;
for(int i=1;i<=n;i++){
string s;
cin>>s;
for(int j=1;j<=m;j++){
if(s[j-1]=='R')a[i][j]=0;
else if(s[j-1]=='G')a[i][j]=1;
else a[i][j]=2;
}
}
int ans=0;
for(int i=1;i<=n;i++){
mem(dp,0);
int x=i,y=1;
while(x>=1&&y<=m){
dp[y][0]=dp[y-1][0];
dp[y][1]=dp[y-1][1];
if(a[x][y]!=2){
x--;
y++;
continue;
}
if(getU(x,y)!=-1){
dp[y][1]=max(dp[y][1],max(dp[y-1][0],dp[y-1][1])+1);
}
if(getL(x,y)!=-1){
dp[y][0]=max(dp[y][0],dp[y-1][0]+1);
if(y-3>=0)dp[y][0]=max(dp[y][0],dp[y-3][1]+1);
}
x--;
y++;
}
y--;
ans+=max(dp[y][0],dp[y][1]);
}
for(int j=2;j<=m;j++){
mem(dp,0);
int x=n,y=j;
while(x>=1&&y<=m){
dp[y][0]=dp[y-1][0];
dp[y][1]=dp[y-1][1];
if(a[x][y]!=2){
x--;
y++;
continue;
}
if(getU(x,y)!=-1){
dp[y][1]=max(dp[y][1],max(dp[y-1][0],dp[y-1][1])+1);
}
if(getL(x,y)!=-1){
dp[y][0]=max(dp[y][0],dp[y-1][0]+1);
if(y-3>=0)dp[y][0]=max(dp[y][0],dp[y-3][1]+1);
}
x--;
y++;
}
y--;
ans+=max(dp[y][0],dp[y][1]);
}
cout<<ans;
}
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
// prec();
int t=1;
// cin>>t;
while(t--)solve();
}
