1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
#include <bits/stdc++.h>


using namespace std;
#define ll long long
#define ld long double
#define all(a) (a).begin(), (a).end()
#define allr(a) (a).rbegin(), (a).rend()
#define F first
#define S second
#define pb push_back
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

/*
#ifndef ONLINE_JUDGE
#include <cpp-dump.hpp>
#endif
*/

constexpr ll mod = 1e9+7;

ll power(ll a, ll b){
    ll res = 1;
    while(b){
        if(b&1) res = res * a % mod;
        a = a * a % mod;
        b >>= 1;
    }
    return res;
}

/*
ll fact[300001];
ll C(ll n, ll k){
    if(k < 0 || k > n) return 0;
    return fact[n] * power(fact[k], mod-2) % mod * power(fact[n-k], mod-2) % mod;
}
*/

struct Phash {
    size_t operator()(const pair<int, int>& p) const {
        return ((size_t)p.F << 20) ^ (size_t)p.S;
    }
};

unordered_set<pii, Phash> blocks;
unordered_set<pii, Phash> inCore;
int n,m,k,q;
ll totalBlocks = 0;

bool is_not_in_core(pii p){
    return inCore.count(p) == 0;
}
bool is_removable(pii p){
    if(inCore.count(p) == 0) return false;
    return ((inCore.count({p.F-1, p.S}) == 0 && inCore.count({p.F+1, p.S}) == 0) || (inCore.count({p.F, p.S-1}) == 0 && inCore.count({p.F, p.S+1}) == 0));
}

int can_be_removed(vector<pii> sources){

    unordered_set<pii, Phash> visited;
    queue<pii> q;
    for(auto &p : sources){
        q.push(p);
        visited.insert(p);
    }
    int removed = 0;
    while(!q.empty()){
        auto p = q.front();
        q.pop();
        if(is_removable(p)){
            removed++;
            inCore.erase(p);
            for(auto &nbr : {pii{p.F-1, p.S}, pii{p.F+1, p.S}, pii{p.F, p.S-1}, pii{p.F, p.S+1}}){
                if(blocks.count(nbr) > 0 && visited.count(nbr) == 0){
                    q.push(nbr);
                    visited.insert(nbr);
                }
            }
        }
    }
    return removed;

}

vector<pii> getComp(pii x) {
    vector<pii> comp;
    unordered_set<pii, Phash> vis;
    queue<pii> q;
    q.push(x);
    vis.insert(x);
    while(!q.empty()){
        pii cur = q.front(); q.pop();
        comp.pb(cur);
        for(auto nbr : {pii{cur.F-1, cur.S}, pii{cur.F+1, cur.S}, pii{cur.F, cur.S-1}, pii{cur.F, cur.S+1}}){
            if(blocks.count(nbr) && !vis.count(nbr)){
                vis.insert(nbr);
                q.push(nbr);
            }
        }
    }
    return comp;
}
 
int peelComp(const vector<pii> &comp){
    queue<pii> q;
    for(auto &p : comp)
        if(is_removable(p))
            q.push(p);
    int removed = 0;
    while(!q.empty()){
        pii cur = q.front(); q.pop();
        if(inCore.count(cur)==0) continue;
        if(!is_removable(cur)) continue;
        inCore.erase(cur);
        removed++;
        for(auto nbr : {pii{cur.F-1, cur.S}, pii{cur.F+1, cur.S}, pii{cur.F, cur.S-1}, pii{cur.F, cur.S+1}}){
            if(blocks.count(nbr))
                q.push(nbr);
        }
    }
    return removed;
}
 
void calcComp(pii x) {
    vector<pii> comp = getComp(x);
    for(auto &p : comp){
        if(blocks.count(p))
            inCore.insert(p);
    }
    peelComp(comp);
}
 
void dzik77() {

    cin >>n >> m >> k >> q;
    for (int i = 0; i < k; i++){
        pii p;
        cin >> p.F >> p.S;
        if(blocks.count(p) == 0){
            blocks.insert(p);
            totalBlocks++;
        }
    }
    unordered_set<pii, Phash> vis;
    for(auto &p : blocks){
        if(!vis.count(p)){
            vector<pii> comp = getComp(p);
            for(auto &x : comp) vis.insert(x);
            for(auto &x : comp) inCore.insert(x);
            peelComp(comp);
        }
    }
    cout << (totalBlocks - (ll)inCore.size()) << '\n';

    while(q--){

        int x,y;
        cin >> x >> y;
        pii p = {x,y};
        unordered_set<pii, Phash> comps;
        if(blocks.count(p) > 0){
            blocks.erase(p);
            inCore.erase(p);
            totalBlocks--;
            for(auto nbr : {pii{p.F-1, p.S}, pii{p.F+1, p.S}, pii{p.F, p.S-1}, pii{p.F, p.S+1}}){
                if(blocks.count(nbr)) comps.insert(nbr);
            }
        } else {
            blocks.insert(p);
            totalBlocks++;
            comps.insert(p);
            for(auto nbr : {pii{p.F-1, p.S}, pii{p.F+1, p.S}, pii{p.F, p.S-1}, pii{p.F, p.S+1}}){
                if(blocks.count(nbr)) comps.insert(nbr);
            }
        }
        for(auto &comp : comps){
            calcComp(comp);
        }
        cout << (totalBlocks - (ll)inCore.size()) << '\n';

    }

}

int32_t main()
{

    ios::sync_with_stdio(0);
    cin.tie(0);

    /*
    fact[0] = 1;
    for (int i = 1; i < 300001; i++){
        fact[i] = fact[i-1] * i % mod;
    }
    */

    int t = 1;
    //cin >> t;
    while(t--)
		dzik77();

    return 0;
}