1 1 2 2
1000000000 1000000000
1
 1 1 1000000000 1000000000
100 1000000000
1
 1 1 10 18
5 6
5
 2 1 1000000000 2000000000
111 999999999
101 999999998
1
 4 13 400 600
13 30
1 19
1 160
1 113
58 73 15 319 194 362 128 157 336 162 77 90 96
 1 15 100 200
283 8
30 58 16 45 80 82 55 95 24 23 86 28 51 47 20
 3 2 300 400
24 68
13 65
15 113
127 177
 1 1 2 1
1 10
1
 4 2 7 15
10 9
4 4
9 3
4 10
1 6
 2 1 1000000000 2000000000
111 1000000000
101 1000000000
5
 2 1 1000000000 2000000000
111 999999998
101 999999998
1
 1 1 1000000000 1000000000
1 1000000000
1

1000000000
 -1
 5
 111
 1
 -1
 -1
 -1
 4
 101
 -1
 -1

#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

#define MOD 1000000007
#define MODSET(d) if ((d) >= MOD) d %= MOD;
#define MODNEGSET(d) if ((d) < 0) d = ((d % MOD) + MOD) % MOD;
#define MODADDSET(d) if ((d) >= MOD) d -= MOD;
#define MODADDWHILESET(d) while ((d) >= MOD) d -= MOD;

#define cint(d) scanf("%d", &d)
#define cint2(a, b) scanf("%d %d", &a, &b)
#define cint3(a, b, c) scanf("%d %d %d", &a, &b, &c)
#define cint4(a, b, c, d) scanf("%d %d %d %d", &a, &b, &c, &d)

#define clong(d) scanf("%lld", &d)
#define clong2(a, b) scanf("%lld %lld", &a, &b)
#define clong3(a, b, c) scanf("%lld %lld %lld", &a, &b, &c)
#define clong4(a, b, c, d) scanf("%lld %lld %lld %lld", &a, &b, &c, &d)

#define foreach(v, c) for(__typeof( (c).begin()) v = (c).begin();  v != (c).end(); ++v)
#define revforeach(v, c) for(__typeof( (c).rbegin()) v = (c).rbegin();  v != (c).rend(); ++v)
#define ALL(v) (v).begin(), (v).end()

#define pb push_back
#define eb emplace_back
#define mp make_pair
#define fi first
#define se second

using namespace std;
using namespace __gnu_pbds;

typedef long long int slong;
typedef pair<int, int> pii;
typedef pair<slong, slong> pll;
typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> pbds;
typedef set<int>::iterator sit;
typedef map<int,int>::iterator mit;
typedef vector<int>::iterator vit;

#ifdef VSP4 
    //Debugging Template Author:  Nikhil Garg
    
    #define debug(args...)	cout << "Line No = " <<  __LINE__ << " >\t"; (Debugger()) , args
	
    class Debugger
    {
        public:
        Debugger(const std::string& _separator = ", ") :
        first(true), separator(_separator){}
        
        template<typename ObjectType>
        Debugger& operator , (const ObjectType& v)
        {
            if(!first)
                std::cout << separator;
            std::cout << v;
            first = false;
            return *this;
        }
        ~Debugger() {  std::cout << endl;}
        
        private:
        bool first;
        std::string separator;
    };
 
    template <typename T1, typename T2>
    inline std::ostream& operator << (std::ostream& os, const std::pair<T1, T2>& p)
    {
        return os << "(" << p.first << ", " << p.second << ")";
    }
 
    template<typename T>
    inline std::ostream &operator << (std::ostream & os,const std::vector<T>& v)
    {
        bool first = true;
        os << "[";
        for(unsigned int i = 0; i < v.size(); i++)
        {
            if(!first)
                os << ", ";
            os << v[i];
            first = false;
        }
        return os << "]";
    }
 
    template<typename T>
    inline std::ostream &operator << (std::ostream & os,const std::set<T>& v)
    {
        bool first = true;
        os << "[";
        for (typename std::set<T>::const_iterator ii = v.begin(); ii != v.end(); ++ii)
        {
            if(!first)
                os << ", ";
            os << *ii;
            first = false;
        }
        return os << "]";
    }
 
    template<typename T1, typename T2>
    inline std::ostream &operator << (std::ostream & os,const std::map<T1, T2>& v)
    {
        bool first = true;
        os << "[";
        for (typename std::map<T1, T2>::const_iterator ii = v.begin(); ii != v.end(); ++ii)
        {
            if(!first)
                os << ", ";
            os << *ii ;
            first = false;
        }
        return os << "]";
    }
    
#else
    #define debug(args...)                  // Just strip off all debug tokens
#endif

#define MAXN 300000
#define LOGN 16
#define SQRTN 317

slong n, k, s, t;
int stations[MAXN+5];
slong axx;

vector<int> difference;

bool canCross(int fuelCapacity)
{
	int i, j;
	slong leftAcc = axx;
	slong time = 0;
	
	for (auto s: difference)
	{
		slong currentFuel = 0;
		
		if (leftAcc >= s)
		{
			leftAcc -= s;
			currentFuel += s*2;
		}
		else
		{
			currentFuel += leftAcc*2;			
			currentFuel += (s - leftAcc);
			leftAcc = 0;
		}
		
		if (currentFuel > fuelCapacity)
		{
			return false;
		}
	}
	
	return true;
}

int c[MAXN+5];
int v[MAXN+5];

int main()
{
    #ifdef VSP4
        //freopen("input.txt", "r", stdin);
        //freopen("output.txt", "w", stdout);
    #endif
	
	int i, j, d;
	
	clong4(n, k, s, t);
	
	for (i = 1; i <= n; i++)
	{
		cint2(c[i], v[i]);
	}
	
	stations[0] = 0;
	for (i = 1; i <= k; i++)
	{
		cint(stations[i]);
	}
	stations[k+1] = s;
		
	sort(stations, stations + k+1 + 1);
	
	for (i = 1; i <= k+1; i++)
	{
		int current = stations[i] - stations[i-1];
		difference.pb(current);
	}
	
	sort(ALL(difference));
	
	axx = max(0ll, 2*s - t);
	
	int first = 1;
	int last = 1e9;
	int mid;
	int best = -1;
	
	while (first <= last)
	{
		mid = (first + last)/2;
		
		if (canCross(mid))
		{
			best = mid;
			last = mid-1;
		}
		else
		{
			first = mid+1;
		}
	}
	
	if (best == -1)
	{
		cout << -1;
		return 0;
	}
	
	int price = MOD;
	
	for (i = 1; i <= n; i++)
	{
		if (v[i] >= best)
		{
			price = min(price, c[i]);
		}
	}
	
	if (price == MOD)
	{
		price = -1;
	}
	
	cout << price;
	
    return 0;
}
