#include <bits/stdc++.h>
#include <iostream>
#include<queue>
#include<vector>
#include<utility>
using namespace std;
typedef long long ll;
const int sz=2e5+1;
const int sz1=1e3+10;
const int mod = 2111992;
int n,m;
char g[4000][4001];
char d[3][4001];
int dp[3][4001];
int main(){
cin>>n>>m;
for(int i = 0; i < n; i++){
for(int j = 0; j < m; j++){
cin>>g[i][j];
}
}
int ans = 0;
for(int i = 1; i < n + m - 2; i++){
for(int j = 0; j < 3; j++){
for(int k = 0; k < 4000; k++) d[j][k] = '?';
}
for(int j = 0; j < 3; j++){
for(int k = 0; k < m; k++){
int r = i + j - k - 1;
int c = k;
if(r < 0 or r>=n) continue;
d[j][k] = g[r][c];
}
}
for(int j = 0; j < 3; j++){
for(int k = 0; k < 4000; k++) dp[j][k] = 0;
}
for(int j = 0; j < m; j++){
for(int k = 0; k < 3; k++){
dp[0][j + 1] = max(dp[0][j + 1], dp[k][j]);
if(d[1][j] != 'G') continue;
if(j > 0 and k!= 1 and d[0][j - 1] == 'R' and d[2][j + 1] == 'W'){
dp[2][j + 1] = max(dp[2][j + 1],dp[k][j] + 1);
}
if(k != 2 and d[0][j] == 'R' and d[2][j] == 'W'){
dp[1][j + 1] = max(dp[1][j + 1],dp[k][j] + 1);
}
}
}
ans += max(dp[0][m],max(dp[1][m],dp[2][m]));
}
cout<<ans<<endl;
}
