#include <bits/stdc++.h>
using namespace std;
#define int long long
#define FOR(i, a, b) for(int i=a; i<=b; ++i)
#define sz(A) (int)(A.size())
#define ll long long
#define eb emplace_back
#define pb push_back
#define pi pair<int, int>
#define f first
#define s second
#define rs resize
#define V vector
const int maxn=3e3+3;
int n, m;
int A[maxn][maxn];
bool poz[maxn][maxn], pio[maxn][maxn];
V<pi> wspol[2*maxn];
int dp[maxn][3];
signed main() {
cin.tie(0) -> ios_base::sync_with_stdio(0);
cin >> n >> m;
FOR(i, 1, n) {
FOR(j, 1, m) {
wspol[i+j].pb({i, j});
char typ;
cin >> typ;
int a=0;
if(typ=='R') a=1;
if(typ=='G') a=2;
if(typ=='W') a=3;
A[i][j]=a;
}
}
FOR(i, 1, 2*maxn-1) reverse(wspol[i].begin(), wspol[i].end());
FOR(i, 1, n) FOR(j, 1, m) {
if(A[i][j]!=2) continue;
if(A[i][j-1]==1 && A[i][j+1]==3) poz[i][j]=1;
if(A[i-1][j]==1 && A[i+1][j]==3) pio[i][j]=1;
}
int odp=0;
FOR(S, 2, n+m) {
if(sz(wspol[S])==0) continue;
FOR(i, 0, maxn-1) FOR(j, 0, 2) dp[i][j]=0;
int w=0;
FOR(i, 1, sz(wspol[S])) {
auto [ii, jj] = wspol[S][i-1];
dp[i][0]=max({dp[i-1][0], dp[i-1][1], dp[i-1][2]});
if(pio[ii][jj]) dp[i][1]=max(dp[i-1][0], dp[i-1][1])+1;
if(poz[ii][jj]) dp[i][2]=max(dp[i-1][0], dp[i-1][2])+1;
w=max({w, dp[i][0], dp[i][1], dp[i][2]});
}
odp+=w;
}
cout << odp << '\n';
}
