除了#1其他全WA了，也不知道哪里错了，调了好久了没看出来呜呜

#include<bits/stdc++.h>
using namespace std;
int n, m, f[1030][1030][3], a[110], sum[1030];
inline int read()
{
    int x = 0, f = 1;
    char c = getchar();
    while (c < '0' || c>'9')
    {
        if (c == '-') f = -1;
        c = getchar();
    }
    while (c >= '0' && c <= '9')
    {
        x = (x << 3) + (x << 1) + (c ^ '0');
        c = getchar();
    }
    return x * f;
}
inline int getone(int x)
{
    int ans = 0;
    while (x > 0)
    {
        if (x & 1 == 1)ans++;
        x = x >> 1;
    }
    return ans;
}
signed main()
{
    n = read();
    m = read();
    for (int i = 1;i <= n;++i)
    {
        for (int j = 1;j <= m;++j)
        {
            char x;
            cin >> x;
            a[i] <<= 1;
            a[i] += (x == 'H' ? 1 : 0);
        }
    }
    for (int i = 0;i < (1 << m);++i)
    {
        sum[i] = getone(i);
    }
    for (int i = 0;i < (1 << m);++i)
    {
        if ((i & a[1]) != 0 || (i & (i << 1)) != 0 || (i & (i << 2)) != 0) continue;
        f[0][i][1] = sum[i];
    }
    for (int i = 0;i <= (1 << m);++i)
    {
        for (int j = 0;j < (1 << m);++j)
        {
            if ((i & j) != 0 || (i & a[1]) != 0 || (j & a[2]) != 0 || (i & (i << 1)) != 0 || (i & (i << 2)) != 0 || (j & (j << 1)) != 0 || (j & (j << 2)) != 0) continue;
            f[i][j][2] = sum[i] + sum[j];
        }
    }
    for (int i = 3;i <= n;++i)
    {
        for (int j = 0;j < (1 << m);++j)//上一行
        {
            if ((j & a[i - 1]) != 0 || (j & (j << 1)) != 0 || (j & (j << 2)) != 0) continue;
            for (int k = 0;k < (1 << m);++k)//当前
            {
                if ((k & a[i]) != 0 || k & j != 0 || (k & (k << 1)) != 0 || (k & (k << 2)) != 0) continue;
                for (int l = 0;l < (1 << m);++l)//上面的上面
                {
                    if ((l & a[i - 2]) != 0 || (l & j) != 0 || (l & k) != 0 || (l & (l << 1)) != 0 || (l & (l << 2)) != 0) continue;
                    f[j][k][i % 3] = max(f[j][k][i % 3], f[l][j][(i - 1) % 3] + sum[k]);
                }
            }
        }
    }
    int ans = -114514;
    for (int i = 0;i < (1 << m);++i)
    {
        for (int j = 0;j < (1 << m);++j)
        {
            ans = max(f[i][j][n % 3], ans);
        }
    }
    printf("%d", ans);
    return 0;
}