#include <bits/stdc++.h>
using namespace std;
char a[3005][3005];
int type[3005][3005];
int dp[3005][4];
int main(){
//ios_base::sync_with_stdio(false);
//cin.tie(NULL);
//cout.tie(NULL);
int r, c;
cin>>r>>c;
for(int i=1;i<=r;i++){
for(int j=1;j<=c;j++){
cin>>a[i][j];
}
}
memset(type, 0, sizeof type);
for(int i=1;i<=r;i++){
for(int j=1;j<=c;j++){
if(a[i][j]=='G'){
if(a[i-1][j]=='R' && a[i+1][j]=='W') type[i][j]+=1;
if(a[i][j-1]=='R' && a[i][j+1]=='W') type[i][j]+=2;
}
}
}
int ans=0;
vector<int>v;
for(int i=2;i<=r+c;i++){
int x, y;
if(i<=c) x=1, y=i-1;
else x=i-c, y=c;
v.clear();
while(x<=r && y>=1){
v.push_back(type[x][y]);
//cout<<x<<" "<<y<<endl;
x++, y--;
}
int n=v.size();
dp[0][0]=dp[0][1]=dp[0][2]=0;
for(int i=0;i<n;i++){
dp[i+1][0]=max({dp[i][0], dp[i][1], dp[i][2]});
dp[i+1][1]=0;
dp[i+1][2]=0;
if(v[i]==1 || v[i]==3) dp[i+1][1]=max(dp[i][1], dp[i][0])+1;
if(v[i]==2 || v[i]==3) dp[i+1][2]=max(dp[i][2], dp[i][0])+1;
}
ans+=max({dp[n][0], dp[n][1], dp[n][2]});
//cout<<ans<<endl;
}
cout<<ans;
}
