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

#define all(x) begin(x),end(x)
#define pb push_back
#define st first
#define nd second

typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

const int INF = 2e9;
const ll LLINF = 2e18;

int calculate(set<pii> s)
{
    bool change=true;
    int res=0;
    while(change)
    {
        change=false;
        set<pii> t=s;
        for(auto p: s)
        {
            pii l={p.st,p.nd-1}, r={p.st,p.nd+1}, u={p.st-1,p.nd}, d={p.st+1,p.nd};
            if((!s.contains(l)&&!s.contains(r))||(!s.contains(u)&&!s.contains(d)))
            {
                t.erase(p);
                ++res;
                change=true;
            }
        }
        s=t;
    }
    return res;
}

void solve()
{
    int n,m,k,q;
    cin>>n>>m>>k>>q;
    set<pii> s;
    for(int i=0; i<k; ++i)
    {
        int x,y;
        cin>>x>>y;
        s.insert({x,y});
    }

    int res=calculate(s);
    cout<<res<<"\n";
    
    while(q--)
    {
        pii p;
        cin>>p.st>>p.nd;
        pii l={p.st,p.nd-1}, r={p.st,p.nd+1}, u={p.st-1,p.nd}, d={p.st+1,p.nd};
        if(s.contains(p))
        {
            s.erase(p);
            if((!s.contains(l)&&!s.contains(r))||(!s.contains(u)&&!s.contains(d)))
                res-=1;
            else
                res=calculate(s);
        }
        else
        {
            s.insert(p);
            if((!s.contains(l)&&!s.contains(r))||(!s.contains(u)&&!s.contains(d)))
                res+=1;
            else
                res=calculate(s);
        }
        cout<<res<<"\n";
    }
}

int main()
{
    ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
    int z=1;
    //cin>>z;
    while(z--)
        solve();
    return 0;
}