//#define LOCAL

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define MAX 1557557
#define MAXS 20
#define ln '\n'

#ifdef LOCAL
#define DEBUG(a) cout<<a
#else
#define DEBUG(a) 1557
#endif

int C[MAX];
int T[MAX];
ll TS[MAX];
int D[MAX];
int N, M, K, P;
int L[MAX];
int R[MAX];
int smx[MAX];
ll sp[MAX][MAXS];
int ban[MAX];
int pv[MAX];
int ne[MAX];
int ichk[MAX];
int dis(int l, int r) {
	if(l<=r) return r-l;
	else return r+N-l;
}
bool chk(ll m) {
	DEBUG(m<<ln);
	int i, j;
	for(i=1;i<=K;i++) {
		int loc = D[i]+N;
		int ind1, ind2;
		ind1 = lower_bound(TS+1, TS+N*3+1, TS[loc-1]-m)-TS+1;
		ind2 = upper_bound(TS+1, TS+N*3+1, TS[loc]+m)-TS-1;
		L[i] = (ind1-1)%N+1;
		R[i] = (ind2-1)%N+1;
		if(dis(L[i], D[i])+dis(D[i], R[i])>=N-1){
			ichk[i] = 1;
		}
		else {
			ichk[i]=0;
			L[i] = ne[L[i]];
			R[i] = pv[R[i]];
		}
	}
	for(i=1;i<=N*2+1;i++) smx[i] = N*3;
	for(i=1;i<=K;i++) {
		if(ichk[i]) continue;
		int l, r;
		l = L[i];
		r = R[i];
		if(l>r) r+=N;
		smx[L[i]-1] = min(smx[L[i]-1], r);
		smx[L[i]-1+N] = min(smx[L[i]-1+N], r+N);
		DEBUG(L[i]<<' '<<R[i]<<ln);
	}
	for(i=N*2;i>=0;i--) smx[i] = min(smx[i], smx[i+1]);
	for(i=1;i<=N;i++) sp[i][0] = smx[i]-i;
	for(i=1;i<=N;i++) DEBUG(sp[i][0]<<' ');
	DEBUG(ln);
	for(j=1;j<MAXS;j++) {
		for(i=1;i<=N;i++) {
			int n = (i+sp[i][j-1]-1)%N;
			n++;
			sp[i][j] = sp[i][j-1]+sp[n][j-1];
		}
	}
	for(i=1;i<=N;i++) {
		int v=i;
		ll sum=0;
		for(j=0;j<MAXS;j++) {
			if(P>>j&1){
				sum+=sp[v][j];
				int n = (v+sp[v][j]-1)%N;
				n++;
				v = n;
			}
		}
		if(sum>=N) return true;
	}
	return false;
}
signed main(){
	ios::sync_with_stdio(false), cin.tie(0);
	cin>>N>>M>>K>>P;
	int i;
	ll l, r;
	l = -1;
	r = N;
	for(i=1;i<=M;i++) cin>>C[i]>>T[i], r+=T[i], ban[C[i]]=1, ban[C[i]+N] = 1;
	for(i=1;i<=N*2;i++) {
		if(ban[i]) pv[i] = pv[i-1];
		else pv[i] = i;
	}
	for(i=N*2;i>=1;i--) {
		if(ban[i]) ne[i] = ne[i+1];
		else ne[i] = i;
	}
	for(i=1;i<=N*2;i++) {
		if(!ne[i]) ne[i] = ne[i+N];
		if(!pv[i]) pv[i] = pv[i+N];
		ne[i]--;
		pv[i]--;
		ne[i]%=N;
		pv[i]%=N;
		ne[i]++;
		pv[i]++;
	}
	for(i=1;i<=K;i++) cin>>D[i];
	for(i=1;i<=M;i++) TS[C[i]]=TS[C[i]+N]=TS[C[i]+N*2] = T[i];
	for(i=1;i<=N*3;i++) TS[i] += TS[i-1];
	for(i=1;i<=N*3;i++) TS[i]+=i;
	while(r-l>1) {
		ll m = l+r>>1;
		if(chk(m)) r = m;
		else l = m;
	}
	cout<<r;
}