#include<bits/stdc++.h>
using namespace std;
template <typename T> inline void read(T& A){T x=0,f=1;char ch=getchar();while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}while(ch>='0'&&ch<='9')x=(x<<1)+(x<<3)+(ch^48),ch=getchar();A=x*f;}
template <typename T> inline void read(T& A,T& B){read(A),read(B);}
template <typename T> inline void read(T& A,T& B,T& C){read(A),read(B),read(C);}
template <typename T> inline void write(T a){if(a<0)putchar('-'),a=-a;if(a>9)write(a/10);putchar(a%10+'0');}
int n,m,a,b;
int A[1510][1510];
int x[500010];
int y[500010];
int main(){
	read(a,b);
	read(n,m);
	for(int i=1;i<=n;i++){
		read(x[i],y[i]);
		A[x[i]][y[i]]=2;
	}
	for(int i=1;i<=m;i++){
		int u,v;
		read(u,v);
		A[u][v]=1;
	}
	for(int i=1;i<=n;i++){
		int lef=x[i]-1;
		while(lef>=1&&A[lef][y[i]]!=1&&A[lef][y[i]]!=2){
			A[lef][y[i]]=3;
			lef--;
		}
		int rig=x[i]+1;
		while(rig<=a&&A[rig][y[i]]!=1&&A[rig][y[i]]!=2){
			A[rig][y[i]]=3;
			rig++;
		}
		lef=y[i]-1;
		while(lef>=1&&A[x[i]][lef]!=1&&A[x[i]][lef]!=2){
			A[x[i]][lef]=3;
			lef--;
		}
		rig=y[i]+1;
		while(rig<=b&&A[x[i]][rig]!=1&&A[x[i]][rig]!=2){
			A[x[i]][rig]=3;
			rig++;
		}
	}
	int ans=0;
	for(int i=1;i<=a;i++){
		for(int j=1;j<=b;j++){
			ans+=(A[i][j]==2||A[i][j]==3);
		}
	}
	cout<<ans;
	return 0;
}

/*
#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
//*/
 
#include <bits/stdc++.h>
 
// #include <atcoder/all>
 
using namespace std;
// using namespace atcoder;
 
#define DEBUG(x) cerr<<#x<<": "<<x<<endl;
#define DEBUG_VEC(v) cerr<<#v<<":";for(int i=0;i<v.size();i++) cerr<<" "<<v[i]; cerr<<endl;
#define DEBUG_MAT(v) cerr<<#v<<endl;for(int i=0;i<v.size();i++){for(int j=0;j<v[i].size();j++) {cerr<<v[i][j]<<" ";}cerr<<endl;}
typedef long long ll;
#define int ll
 
#define vi vector<int>
#define vl vector<ll>
#define vii vector< vector<int> >
#define vll vector< vector<ll> >
#define vs vector<string>
#define pii pair<int,int>
#define pis pair<int,string>
#define psi pair<string,int>
#define pll pair<ll,ll>
template<class S, class T> pair<S, T> operator+(const pair<S, T> &s, const pair<S, T> &t) { return pair<S, T>(s.first + t.first, s.second + t.second); }
template<class S, class T> pair<S, T> operator-(const pair<S, T> &s, const pair<S, T> &t) { return pair<S, T>(s.first - t.first, s.second - t.second); }
template<class S, class T> ostream& operator<<(ostream& os, pair<S, T> p) { os << "(" << p.first << ", " << p.second << ")"; return os; }
#define X first
#define Y second
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define rep1(i,n) for(int i=1;i<=(int)(n);i++)
#define rrep(i,n) for(int i=(int)(n)-1;i>=0;i--)
#define rrep1(i,n) for(int i=(int)(n);i>0;i--)
#define REP(i,a,b) for(int i=a;i<b;i++)
#define in(x, a, b) (a <= x && x < b)
#define all(c) c.begin(),c.end()
void YES(bool t=true) {cout<<(t?"YES":"NO")<<endl;}
void Yes(bool t=true) {cout<<(t?"Yes":"No")<<endl;}
void yes(bool t=true) {cout<<(t?"yes":"no")<<endl;}
void NO(bool t=true) {cout<<(t?"NO":"YES")<<endl;}
void No(bool t=true) {cout<<(t?"No":"Yes")<<endl;}
void no(bool t=true) {cout<<(t?"no":"yes")<<endl;}
template<class T> bool chmax(T &a, const T &b) { if (a<b) { a = b; return 1; } return 0; }
template<class T> bool chmin(T &a, const T &b) { if (a>b) { a = b; return 1; } return 0; }
#define UNIQUE(v) v.erase(std::unique(v.begin(), v.end()), v.end());
const ll inf = 1000000001;
const ll INF = (ll)1e18 + 1;
const long double pi = 3.1415926535897932384626433832795028841971L;
int popcount(ll t) { return __builtin_popcountll(t); }
// int dx[4] = {1, 0, -1, 0}, dy[4] = {0, 1, 0, -1};
// int dx2[8] = { 1,1,0,-1,-1,-1,0,1 }, dy2[8] = { 0,1,1,1,0,-1,-1,-1 };
vi dx = {0, 1, 0, -1}, dy = {-1, 0, 1, 0};
// vi dx2 = { 1,1,0,-1,-1,-1,0,1 }, dy2 = { 0,1,1,1,0,-1,-1,-1 };
struct Setup_io {
    Setup_io() {
        ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
        cout << fixed << setprecision(25);
    }
} setup_io;
const ll MOD = 1000000007;
// const ll MOD = 998244353;
// #define mp make_pair
//#define endl '\n'

ll gcd(ll a, ll b) {
  if (b > a) {
    swap(a, b);
  }
  if (b == 0) return a;
  ll r = a%b;
  while (r != 0) {
    a = b;
    b = r;
    r = a%b;
  }
  return b;
}

ll lcm(ll a, ll b) {
  return (a / gcd(a, b))*b;
}



signed main() {
    int n;
    cin >> n;
    vi a(n);
    rep (i, n) cin >> a[i];

    vi primes;
    REP (i, 2, 51) {
        int x = i;
        bool flag = true;
        for (int j = 2; j < x; j++) {
            if (x % j == 0) {
                flag = false;
            }
        }
        if (flag) primes.push_back(i);
    }

    int m = primes.size();
    ll ans = INF;
    rep (i, 1 << m) {
        ll g = 1;
        rep (j, m) {
            if (i & (1 << j)) g *= primes[j];
        }

        bool flag = true;
        rep (i, n) {
            if (gcd(g, a[i]) == 1) flag = false;
        }
        if (flag) {
            chmin(ans, g);
        }
    }
    cout << ans << endl;
}