#include<iostream> using namespace std; int col[100002],row[1000003]; int main(){ int n,m,x,y; cin>>n>>m>>x>>y; int c=0,r=0; for (int i=1,a;i<=x;i++){ cin>>a; col[a]++; if(col[a]==1) c++; } for (int i=1,a;i<=y;i++){ cin>>a; row[a]++; if(row[a]==1) r++; } cout<<n*m-(c*m+r*n-c*r); return 0; }