1 #include <bits/stdc++.h>
2 #define _for(i,a,b) for(int i = (a);i < b;i ++)
3 #define _rep(i,a,b) for(int i = (a);i > b;i --)
4 #define INF 0x3f3f3f3f
5 #define MOD 1000000007
6 typedef long long ll;
7 using namespace std;
8 inline ll read()
9 {
10 ll ans = 0;
11 char ch = getchar(), last = ' ';
12 while(!isdigit(ch)) last = ch, ch = getchar();
13 while(isdigit(ch)) ans = (ans << 1) + (ans << 3) + ch - '0', ch = getchar();
14 if(last == '-') ans = -ans;
15 return ans;
16 }
17 inline void write(ll x)
18 {
19 if(x < 0) x = -x, putchar('-');
20 if(x >= 10) write(x / 10);
21 putchar(x % 10 + '0');
22 }
23
24 int N,M;
25 int a[1003][1003];
26 int lef[1003][1003];
27 int ri[1003][1003];
28 int up[1003][1003];
29 int main()
30 {
31 N = read(),M = read();
32 _for(i,1,N+1)
33 _for(j,1,M+1)
34 {
35 char c;
36 cin >> c;
37 if(c=='R')
38 a[i][j] = 1;
39 else
40 a[i][j] = 0;
41 }
42
43 _for(j,1,M+1)
44 {
45 if(!a[1][j])
46 up[1][j] = 1;
47 _for(i,2,N+1)
48 if(!a[i][j])
49 up[i][j] = up[i-1][j]+1;
50 }
51
52 _for(i,1,N+1)
53 {
54 if(!a[i][1])
55 lef[i][1] = 1;
56 _for(j,2,M+1)
57 if(!a[i][j])
58 lef[i][j] = lef[i][j-1]+1;
59 }
60
61 _for(i,1,N+1)
62 {
63 if(!a[i][M])
64 ri[i][M] = 1;
65 _rep(j,M-1,0)
66 if(!a[i][j])
67 ri[i][j] = ri[i][j+1]+1;
68 }
69 int ans = 0;
70 _for(i,1,N+1)
71 _for(j,1,M+1)
72 {
73 if(i>1 && !a[i][j] && !a[i-1][j])
74 {
75 lef[i][j] = min(lef[i-1][j],lef[i][j]);
76 ri[i][j] = min(ri[i-1][j],ri[i][j]);
77 }
78 ans = max(ans,up[i][j]*(ri[i][j]+lef[i][j]-1));
79 }
80 write(3*ans);
81 return 0;
82 }
