玄学，我交上去是错的，下了数据自己试就是对的

#include<iostream>
#include<cmath>
#include<algorithm>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<queue>
#include<vector>
#include<deque>
#include<set>
#include<map>
#define N 100005
using namespace std;
int n,m,a[105];
int zt[105],gs[105],cnt;
int f[105][65][65];
void dfs(int y,int num,int g){
    if(y>m){
        zt[++cnt]=num>>(y-m-1);
        gs[cnt]=g;
        return;
    }
    dfs(y+1,num<<1,g);
    dfs(y+3,(num<<1|1)<<2,g+1);
}
int main(){
    scanf("%d%d",&n,&m);
    dfs(1,0,0);
    for(int i=1;i<=n;i++){
        for(int j=1;j<=m;j++){
            char x;
            scanf("%c",&x);
            a[i]<<=1;
            if(x=='P')a[i]|=1;
        }   
    }
    for(int i=1;i<=n;i++){
        for(int j=1;j<=cnt;j++){
            int x=zt[j];
            if((x|a[i])!=a[i])continue;
            for(int k=1;k<=cnt;k++){
                int y=zt[k];
                if((x&y))continue;
                for(int l=1;l<=cnt;l++){
                    int z=zt[l];
                    if((x&z)||(y&z))continue;
                    f[i][j][k]=max(f[i][j][k],f[i-1][k][l]+gs[j]);
                }
            }
        }
    }
    int maxx=0;
    for(int i=1;i<=cnt;i++){
        for(int j=1;j<=cnt;j++){
            if(zt[i]&zt[j])continue;
            maxx=max(f[n][i][j],maxx);
        }
    }
    printf("%d",maxx);
    return 0;
}