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

#define f first
#define s second

typedef long long ll;

const int maxn = 2e5+5;
const ll inf = 1e18+5;


ll n, m, k, p, sz;

ll pfx[maxn], C[maxn], D[maxn], mm[maxn];

ll query(int l, int r){
    if(r < l)return pfx[r]+pfx[n]-pfx[l-1] + (n-l+r);
    else return pfx[r]-pfx[l-1] + (r-l);
}

ll dist(int a, int x, int id){
    return id ?  query(a, x) : query(x, a);
}

int nxt(int x){
    return x == sz-1 ? 0 : x+1;
}

int prv(int x){
    return x == 0 ? sz-1 : x-1;
}

ll st[20][maxn];

ll chk(ll x){
    vector<int> epos;
    for(int i = 1; i <= n; i++)if(pfx[i] == pfx[i-1]){
        epos.push_back(i);
        //cout << i << " ";
    }
    sz = epos.size();
    //cout << "\n";
    int ptr = 0, ptr2 = 0, cnt = 0;
    for(int i = 0; i < epos.size(); i++){
        while(query(epos[i], epos[ptr]) <= x){
            if(ptr == ptr2){
                if(mm[epos[ptr2]])cnt++;
                if(cnt == k)return 1;
                ptr2 = nxt(ptr2);
            }
            ptr = nxt(ptr);
        }
        //cout << cnt << "\n";
        while(query(epos[ptr-1], epos[ptr2]) <= x){
            if(mm[epos[ptr2]])cnt++;
            if(cnt == k)return 1;
            ptr2 = nxt(ptr2);
        }
        if(mm[epos[i]]){
            //cout << x << " " << epos[i] << " " << epos[ptr] << " " << epos[ptr2] << " " << cnt << "\n";
            st[0][mm[epos[i]]-1] = cnt;
            assert(cnt);
            cnt--;
        }
    }
    //for(int i = 0; i < k; i++)st[0][i] = 0;
    for(int i = 1; i < 20; i++){
        for(int j = 0; j < k; j++){
            int nxt = (j+st[i-1][j])%k;
            st[i][j]=st[i-1][j]+st[i-1][nxt];
        }
    }
    int ans = p+1;
    for(int i = 0; i < k; i++){
        int tot = 0, crr = 0;
        for(int j = 19; j >= 0; j--){
            if(st[j][(i+crr)%k]+crr < k){
                crr+=st[j][(i+crr)%k];
                tot+=(1<<j);
            }
        }
        ans = min(ans, tot);
    }
    return ans+1;
}

int main(){
    cin >> n >> m >> k >> p;
    for(int i = 1; i <= m; i++)cin >> C[i] >> pfx[C[i]];
    for(int i = 1; i <= n; i++)pfx[i]+=pfx[i-1];
    if(k == 1){
        cout << 0;
        return 0;
    }
    for(int i = 0; i < k; i++){
        cin >> D[i];
    }
    sort(D, D+k);
    for(int i = 0; i < k; i++)mm[D[i]]=i+1;
    ll l = 0, r = inf;
    while(l < r){
        ll mid = (l+r)>>1;
        if(chk(mid) <= p)r=mid;
        else l = mid+1;
    }
    //cout << query(5, 2) << "\n";
    cout << l << "\n";
}