//Start: 2024-11-11 20:09:33
#include<bits/stdc++.h>
#define For(i,j,k) for(int i=(j);i<=(k);++i)
#define ForDown(i,j,k) for(int i=(j);i>=(k);--i)
#define Debug(fmt, args...) fprintf(stderr,"(func %s, line #%d): " fmt, __func__, __LINE__, ##args),fflush(stderr)
#define debug(fmt, args...) fprintf(stderr,fmt,##args),fflush(stderr)
#define within :
#define LJY main
using namespace std;
typedef long long ll;
const int N=1005;
mt19937 rnd(chrono::system_clock::now().time_since_epoch().count());
inline int read(){
  char ch=getchar();int x=0,f=1;
  while(ch<'0'||ch>'9'){if(ch=='-') f=-1;ch=getchar();}
  while(ch>='0'&&ch<='9')
    x=(x<<3)+(x<<1)+(ch^48),ch=getchar();
  return x*f;
}
int n,m,a[N][N],b[N][N];
pair<int,int>dl[N*N];
int l[N][N],r[N][N],u[N][N],d[N][N];
signed LJY(){
  n=read();m=read();
  For(i,1,n) For(j,1,m){
    a[i][j]=read();
    dl[a[i][j]].first+=i;
    dl[a[i][j]].second+=j;
  }For(i,1,n) For(j,1,m){
    b[i][j]=read();
    dl[b[i][j]].first-=i;
    dl[b[i][j]].second-=j;
  }
  For(i,1,n){
    l[i][1]=1;For(j,2,m) if(dl[a[i][j]]==dl[a[i][j-1]]) l[i][j]=l[i][j-1];else l[i][j]=j;
    r[i][m]=1;ForDown(j,m-1,1) if(dl[a[i][j]]==dl[a[i][j+1]]) r[i][j]=r[i][j+1];else r[i][j]=j;
  }For(i,1,m){
    u[1][i]=1;For(j,2,n) if(dl[a[j][i]]==dl[a[j-1][i]]) u[j][i]=u[j-1][i];else u[j][i]=j;
    d[i][n]=1;ForDown(j,n-1,1) if(dl[a[j][i]]==dl[a[j+1][i]]) d[j][i]=d[j+1][i];else d[j][i]=j;
  }int ans=0;
  For(i,1,n) For(j,1,m) if(l[i][j]==j)
    For(x,j,r[i][j]){
      int U=max(u[i][j],u[i][x]);
      int D=min(d[i][j],d[i][x]);
      ans=max(ans,(D-U+1)*(x-j+1));
    }printf("%d",ans);
  return 0;
}