#include <bits/stdc++.h>

using namespace std;
int main() 
{

    int R,C,K,N;
    cin>>R>>C>>K>>N;

    vector<int> r(R+1,0);
    vector<int> c(C+1,0);
    unordered_map<int, unordered_map<int,int>> m;

    for (int i=0;i<N;++i) 
    {
        int x,y;
        cin>>x>>y;
        r[x]++;
        c[y]++;
        m[x][y]++;
    }

    unordered_map<int, int> rcm;
    unordered_map<int, int> ccm;

    for (int i=1;i<=R;++i) 
    {
        rcm[r[i]]++;
    }

    for (int i=1;i<=C;++i) 
    {
        ccm[c[i]]++;
    }

    long long res=0;

    for (auto& y:rcm) 
    {
        int rc=y.first;
        int r=y.second;

        for (auto& p:ccm) 
        {
            int cc=p.first;
            int co=p.second;

            if (rc+cc==K) 
            {
                res+=static_cast<long long>(r)*co;
            }
        }
    }

    for (auto& rp:m) 
    {
        int x=rp.first;
        for (auto& cp:rp.second) 
        {
            int y=cp.first;
            int cnt=cp.second;

            if (r[x]+c[y]==K) 
            {
                res--;
            } 
            else if (r[x]+c[y]-cnt==K) 
            {
                res++;
            }
        }
    }

    cout<<res<<endl;
    return 0;
}