#include <iostream>
#include <cassert>
#include <algorithm>
#include <string>
#include <bitset>
#include <vector>
#include <cmath>
#include <deque>
#include <queue>
#include <stack>
#include <map>
#include <set>
#ifndef LOCAL
#include <bits/stdc++.h>
#define cerr if(false)cerr
#endif
using namespace std;
using ll = long long;
const int M = 3e3 + 123;
const int N = M*3;
int x[N], y[N], dp[N][2];
int a[M][M];
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
int n, m;
cin >> n >> m;
for (int i = 1 ; i <= n ; ++ i) {
for (int j = 1 ; j <= m ; ++ j) {
char c;
cin >> c;
if (c == 'R') a[i][j] = 0;
else if (c == 'G') a[i][j] = 1;
else a[i][j] = 2;
}
}
int ans = 0;
for (int ij = 2 ; ij <= n + m ; ++ ij) {
cerr << "----\n";
cerr << ij << "\n";
for (int i = 0 ; i <= ij + 6 ; ++ i) {
x[i] = y[i] = 0;
}
int l = 4;
for (int i = 1 ; i <= n ; ++ i) {
int j = ij - i;
if (j < 0 || j > m) continue;
cerr << i << " " << j << " \n";
l++;
x[l] = (a[i][j] == 0 && a[i + 1][j] == 1 && a[i + 2][j] == 2);
y[l] = (a[i][j] == 0 && a[i][j + 1] == 1 && a[i][j + 2] == 2);
swap(x[l], y[l]);
}
for (int i = 0 ; i <= l ; ++ i) {
dp[i][0] = dp[i][1] = 0;
}
for (int i = 4 ; i <= l ; ++ i) {
dp[i][0] = max(dp[i][0], dp[i - 1][0] + x[i]);
dp[i][1] = max(dp[i][1], dp[i - 1][1] + y[i]);
dp[i][0] = max(dp[i][0], dp[i - 3][1] + x[i]);
dp[i][1] = max(dp[i][1], dp[i - 1][0] + y[i]);
}
int cur = 0;
for (int i = 1 ; i <= l ; ++ i) {
cur = max(cur, dp[i][0]);
cur = max(cur, dp[i][1]);
}
for (int i = 0 ; i <= l ; ++ i) {
cerr << x[i] << " " << y[i] << " | " << dp[i][0] << " " << dp[i][1] << endl;
}
for (int i = 1 ; i <= n ; ++ i) {
for (int j = 1 ; j <= m ; ++ j) {
cerr << a[i][j] << " ";
}
cerr << "\n";
}
ans += cur;
cerr << cur << "\n---\n";
}
cout << ans;
}
