//
// Created by liuhao on 2024/5/14.
//
#pragma GCC optimize(1)
#pragma GCC optimize(2)
#pragma GCC optimize(3, "Ofast", "inline")
#include<bits/stdc++.h>
using namespace std;
#define PII pair<int,int>
#define fi first
#define se second
#define ios ios::sync_with_stdio(0),cin.tie(0),cout.tie(0)
#define int long long
#define endl '\n'
#define vii vector<vector<int>>
template<class Node>
struct SegmentTree {
#define mid ((l+r)/2)
	int n;
	std::vector<Node> node;
	SegmentTree() : n(0) {}
	SegmentTree(int n_, Node v_ = Node()) {
		init(n_, v_);
	}
	template<class T>
	SegmentTree(std::vector<T> init_) {
		init(init_);
	}
	void init(int n_, Node v_ = Node()) {
		init(std::vector(n_, v_));
	}
	template<class T>
	void init(std::vector<T> init_) {
		n = init_.size()-1;
		node.assign(4 << std::__lg(n+1), Node());
		std::function<void(int, int, int)> build = [&](int p, int l, int r) {
			if (r == l)return void(node[p] = init_[l]);
			build(2 * p, l, mid);
			build(2 * p + 1, mid + 1, r);
			pushup(p);
		};
		build(1, 0, n);
	}
	void pushup(int p) {
		node[p] = node[2 * p] + node[2 * p + 1];
	}
	void upd(int p, int l, int r, int x, const Node &v) {
		if (r == l)return void(node[p] = v);
		if (x <= mid) upd(2 * p, l, mid, x, v);
		else upd(2 * p + 1, mid + 1, r, x, v);
		pushup(p);
	}
	void upd(int p, const Node &v) {
		upd(1, 0, n, p, v);
	}
	Node que(int p, int l, int r, int x, int y) {
		if (l > y || r < x)return Node();
		if (l >= x && r <= y)return node[p];
		return que(2 * p, l, mid, x, y) + que(2 * p + 1, mid + 1, r, x, y);
	}
	Node que(int l, int r) {
		return que(1, 0, n, l, r);
	}
	template<class F>
	int findFirst(int p, int l, int r, int x, int y, F pred) {
		if (l > y || r < x || !pred(node[p]))return -1;
		if (r == l)return l;
		int res = findFirst(2 * p, l, mid, x, y, pred);
		if (res == -1)res = findFirst(2 * p + 1, mid + 1, r, x, y, pred);
		return res;
	}
	template<class F>
	int findFirst(int l, int r, F pred) {//区间第一个满足条件的数
		return findFirst(1, 0, n, l, r, pred);
	}
	template<class F>
	int findLast(int p, int l, int r, int x, int y, F pred) {
		if (l > y || r < x || !pred(node[p]))return -1;
		if (r == l)return l;
		int res = findLast(2 * p + 1, mid + 1, r, x, y, pred);
		if (res == -1) res = findLast(2 * p, l, mid, x, y, pred);
		return res;
	}
	template<class F>
	int findLast(int l, int r, F pred) {//区间最后一个不满足条件的数
		return findLast(1, 0, n, l, r, pred);
	}
};
const int inf = 1e18;
struct Node {
	int minn=inf;
};
Node operator+(Node a, Node b) {
	Node c;
	c.minn=max(a.minn,b.minn);
	return c;
}
signed main() {
#ifdef Liuhao
	freopen("in.txt", "r", stdin);
#else
	ios;
#endif
	int n,m;
	cin>>n>>m;
	vector a(n+1,vector<int>(m+1));
	vector b(n+1,vector<int>(m+1));
	vector<int>c(n*m+1);
	for (int i = 1; i <= n; i++) {
		for (int j = 1; j <= m; j++) {
			cin>>a[i][j];
			c[a[i][j]]=(i-1)*m+j;
		}
	}
	for (int i = 1; i <= n; i++) {
		for (int j = 1; j <= m; j++) {
			cin>>b[i][j];
			b[i][j]=c[b[i][j]];
		}
	}
	vector l(n+1,vector<int>(m+1));
	vector r(n+1,vector<int>(m+1));
	vector down(n+1,vector<int>(m+1));
	for(int i=1;i<=m;i++){
		down[n][i]=1;
		for(int j=n-1;j>=1;j--){
			if(b[j+1][i]-b[j][i]==m)down[j][i]=down[j+1][i]+1;
			else down[j][i]=1;
		}
	}
	int ans=0;
	for (int i = 1; i <= n; i++) {
		l[i][1]=1;
		for (int j = 2; j <= m; j++) {
			if(b[i][j]-b[i][j-1]==1)l[i][j]=l[i][j-1]+1;
			else l[i][j]=1;
		}
		r[i][m]=1;
		for(int j=m-1;j>=1;j--){
			if(b[i][j+1]-b[i][j]==1)r[i][j]=r[i][j+1]+1;
			else r[i][j]=1;
		}
	}
	
	for (int i = 1; i <= n; i++) {
		SegmentTree<Node>seg(m+2);
		seg.upd(0,{0});
		seg.upd(m+1,{0});
		for (int j = 1; j <= m; j++) seg.upd(j,{down[i][j]});
		for(int j=1;j<=m;j++){
			int l0=seg.findFirst(0,j,[&](Node x){
				if(x.minn>=down[i][j])return 1;
				return 0;
			});
			int r0=seg.findLast(j,m+1,[&](Node x){
				if(x.minn>=down[i][j])return 1;
				return 0;
			});
			l0=min(j-l0+1,l[i][j]);
			r0=min(r0+1-j,r[i][j]);
			l0=min((b[i][j]-1)%m+1,l0);
			r0=min(m-((b[i][j]-1)%m+1)+1,r0);
			ans=max(ans,(l0+r0-1)*down[i][j]);
		}
	}
	cout<<ans<<endl;
	
	return 0;
}