#include <bits/stdc++.h>
#define int long long
int dp[3001][3001][3];
bool dango[3001][3001][2];
signed main() {
int n,m;
std::cin >> n >> m;
std::vector<std::string> grid;
std::string dummy;
for(int i=0;i<=m;i++)dummy.push_back('X');
grid.push_back(dummy);
for(int i=0;i<n;i++){
std::string s;
std::cin >> s;
grid.push_back("X"+s+"X");
}
grid.push_back(dummy);
int best = 0;
for(int i=1;i<=n;i++){
for(int j=m;j>0;j--){
if(grid[i][j]=='G'&&grid[i][j-1]=='R'&&grid[i][j+1]=='W')dango[i][j][0]=true;
if(grid[i][j]=='G'&&grid[i-1][j]=='R'&&grid[i+1][j]=='W')dango[i][j][1]=true;
dp[i][j][0] = dp[i-1][j+1][0];
dp[i][j][0] = std::max(dp[i][j][0],dp[i-1][j+1][1]);
dp[i][j][0] = std::max(dp[i][j][0],dp[i-1][j+1][2]);
if(dango[i][j][0])
dp[i][j][1] = dp[i-1][j+1][0]+1;
if(dango[i][j][0])
dp[i][j][1] = std::max(dp[i][j][1],dp[i-1][j+1][1]+1);
if(dango[i][j][1])
dp[i][j][2] = dp[i-1][j+1][0]+1;
if(dango[i][j][1])
dp[i][j][2] = std::max(dp[i][j][2],dp[i-1][j+1][2]+1);
}
}
// for(int i=1;i<=n;i++){
// for(int j=1;j<=m;j++){
// std::cout << dp[i][j][0] << '|' << dp[i][j][1] << '|' << dp[i][j][2] << ' ';
// }std::cout << '\n';
// }
int sum=0;
for(int i=1;i<=n;i++){
sum+=std::max(dp[i][1][0],std::max(dp[i][1][1],dp[i][1][2]));
}
//std::cout << sum << '\n';
for(int j=1;j<=m;j++){
sum+=std::max(dp[n][j][0],std::max(dp[n][j][1],dp[n][j][2]));
}
//std::cout << sum << '\n';
sum-=std::max(dp[n][1][0],std::max(dp[n][1][1],dp[n][1][2]));
std::cout << sum;
}
