//And He found you lost and guided [you] [93:07]

//#pragma GCC optimize ("Ofast")
//#pragma GCC target ("avx2")
//#pragma GCC optimize("unroll-loops")

#include<bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef long double ld;
typedef pair<ll,ll> pll;
typedef pair<int,int> pii;
typedef vector<ll> vll;
typedef vector<int> vii;
typedef map<int,int> mpi;
typedef map<ll,ll> mpl;
typedef unordered_map<int,int> umpi;
typedef unordered_map<ll,ll> umpl;

#define modu 998244353 
#define mod 1000000007
#define eps 1e-7
#define inf 1000000000000000006
#define ff first
#define ss second
#define pb push_back
#define all(v) v.begin(), v.end()
#define fastio ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL)
#define endl '\n'
// #define pi acos(-1.0)
#define dec(n) fixed << setprecision(n)
#define N 500005
#define int long long

int n,m,a[1005][1005],b[1005][1005];
pair<int,int> c[1005][1005];
pair<int,int> mp[1000005];
pair<int,int> ans[1005][1005];
int val[1005][1005];

void solve(){
    cin >> n >> m;
    for(int i=1;i<=n;i++){
        for(int j=1;j<=m;j++) cin >> a[i][j];
    }

    for(int i=1;i<=n;i++){
        for(int j=1;j<=m;j++){
            cin >> b[i][j];
            mp[b[i][j]]={i,j};   
        } 
    }

    
    for(int i=1;i<=n;i++){
        for(int j=1;j<=m;j++){
            c[i][j]={mp[a[i][j]].ff-i,mp[a[i][j]].ss-j};
            if(i==1) val[i][j]=1;
            else{
                if(c[i-1][j]==c[i][j]) val[i][j]=val[i-1][j]+1;
                else val[i][j]=1;
            }
        }
    }

    int ans=0;
    for(int i=1;i<=n;i++){
        int lst[1005],dst[1005];
        stack<pair<int,int>> st;
        for(int j=1;j<=m;j++){
            if(c[i][j-1]!=c[i][j]){
                while(!st.empty()) st.pop();
                st.push({0,j-1});  
            } 
            while(!st.empty() && st.top().ff>=val[i][j]) st.pop();
            if(!st.empty()) lst[j]=st.top().ss;
            else lst[j]=j-1;
            st.push({val[i][j],j});
        }

        while(!st.empty()) st.pop();

        for(int j=m;j>0;j--){
            if(c[i][j+1]!=c[i][j]){
                while(!st.empty()) st.pop();
                st.push({0,j+1});  
            } 
            while(!st.empty() && st.top().ff>=val[i][j]) st.pop();
            if(!st.empty()) dst[j]=st.top().ss;
            else dst[j]=j+1;
            st.push({val[i][j],j});
        }

        for(int j=1;j<=m;j++){
            // cout << val[i][j] << " " << dst[j] << " " << lst[j] << "  -  ";
            ans=max(ans,(dst[j]-lst[j]-1)*val[i][j]);
        }
        // cout << endl;


    }

    cout << ans << endl;








}


signed main(){
    fastio;
    //srand(chrono::steady_clqk::now().time_since_epqh().count());
    // fflush(stdout);

    int T=1,cs=0;
    // cin >> T;
    while(T--){
        //cout << "Case " << ++cs << ": " ; 
        solve();
    } 
    return 0;
}