#include <bits/stdc++.h>
using namespace std;
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
int n, m;
cin >> n >> m;
char a[n+1][m+1];
for (int i = 1; i <= n; ++i) {
for (int j = 1; j <= m; ++j) {
cin >> a[i][j];
}
}
// if (n == 5 && m == 3000) {
// cout << "xxxx" << endl;
// return 0;
// }
int H[n+1][m+1][2];
for (int i = 1; i <= n; ++i) {
for (int j = 1; j <= m; ++j) {
H[i][j][0] = (j >= 2 && j <= m-1 && a[i][j] == 'G' && a[i][j-1] == 'R' && a[i][j+1] == 'W');
H[i][j][1] = (i >= 2 && i <= n-1 && a[i][j] == 'G' && a[i-1][j] == 'R' && a[i+1][j] == 'W');
}
}
int ans = 0;
for (int k = 2; k <= n+m; k++) {
array<int, 3> dp = {0, 0, 0};
// if (k >= 2 && n == 5 && m == 3000) {
// cout << "xxxx" << endl;
// return 0;
// }
for (int i = max(1, k - m); i < min(k, n+1); ++i) {
array<int, 3> qp = {max({dp[0], dp[1], dp[2]}),
H[i][k-i][1] + max({dp[0], dp[1]}),
H[i][k-i][0] + max({dp[0], dp[2]})};
dp = qp;
}
ans += max({dp[0], dp[1], dp[2]});
}
cout << ans << '\n';
}
