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

import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Arrays;
import java.io.IOException;
import java.util.function.IntPredicate;
import java.io.Serializable;
import java.io.UncheckedIOException;
import java.io.Closeable;
import java.io.Writer;
import java.io.OutputStreamWriter;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 */
public class Main {
    public static void main(String[] args) throws Exception {
        Thread thread = new Thread(null, new TaskAdapter(), "", 1 << 29);
        thread.start();
        thread.join();
    }

    static class TaskAdapter implements Runnable {
        @Override
        public void run() {
            InputStream inputStream = System.in;
            OutputStream outputStream = System.out;
            FastInput in = new FastInput(inputStream);
            FastOutput out = new FastOutput(outputStream);
            ARoadToCinema solver = new ARoadToCinema();
            solver.solve(1, in, out);
            out.close();
        }
    }

    static class ARoadToCinema {
        public void solve(int testNumber, FastInput in, FastOutput out) {
            int n = in.ri();
            int k = in.ri();
            int s = in.ri();
            int t = in.ri();
            int[][] car = new int[n][2];
            for (int i = 0; i < n; i++) {
                for (int j = 0; j < 2; j++) {
                    car[i][j] = in.ri();
                }
            }
            int[] gas = new int[k + 1];
            for (int i = 0; i < k; i++) {
                gas[i] = in.ri();
            }
            gas[k] = s;
            Randomized.shuffle(gas);
            Arrays.sort(gas);
            IntPredicate predicate = m -> {
                int bestCap = -1;
                for (int i = 0; i < n; i++) {
                    if (car[i][0] <= m) {
                        bestCap = Math.max(bestCap, car[i][1]);
                    }
                }
                if (bestCap < 0) {
                    return false;
                }
                int time = 0;
                int now = 0;
                for (int i = 0; i <= k; i++) {
                    int to = gas[i];
                    int len = to - now;
                    if (len > bestCap) {
                        return false;
                    }
                    time += 2 * len - Math.min(len, bestCap - len);
                    now = to;
                }
                return time <= t;
            };
            int ans = BinarySearch.firstTrue(predicate, 0, (int) 1e9);
            if (ans > 1e9) {
                out.println(-1);
                return;
            }
            out.println(ans);
        }

    }

    static class DigitUtils {
        private DigitUtils() {
        }

        public static int floorAverage(int x, int y) {
            return (x & y) + ((x ^ y) >> 1);
        }

    }

    static class FastOutput implements AutoCloseable, Closeable, Appendable {
        private static final int THRESHOLD = 1 << 13;
        private final Writer os;
        private StringBuilder cache = new StringBuilder(THRESHOLD * 2);

        public FastOutput append(CharSequence csq) {
            cache.append(csq);
            return this;
        }

        public FastOutput append(CharSequence csq, int start, int end) {
            cache.append(csq, start, end);
            return this;
        }

        private void afterWrite() {
            if (cache.length() < THRESHOLD) {
                return;
            }
            flush();
        }

        public FastOutput(Writer os) {
            this.os = os;
        }

        public FastOutput(OutputStream os) {
            this(new OutputStreamWriter(os));
        }

        public FastOutput append(char c) {
            cache.append(c);
            afterWrite();
            return this;
        }

        public FastOutput append(int c) {
            cache.append(c);
            afterWrite();
            return this;
        }

        public FastOutput append(String c) {
            cache.append(c);
            afterWrite();
            return this;
        }

        public FastOutput println(int c) {
            return append(c).println();
        }

        public FastOutput println() {
            return append(System.lineSeparator());
        }

        public FastOutput flush() {
            try {
                os.append(cache);
                os.flush();
                cache.setLength(0);
            } catch (IOException e) {
                throw new UncheckedIOException(e);
            }
            return this;
        }

        public void close() {
            flush();
            try {
                os.close();
            } catch (IOException e) {
                throw new UncheckedIOException(e);
            }
        }

        public String toString() {
            return cache.toString();
        }

    }

    static class BinarySearch {
        private BinarySearch() {
        }

        public static int firstTrue(IntPredicate predicate, int l, int r) {
            assert l <= r;
            while (l != r) {
                int mid = DigitUtils.floorAverage(l, r);
                if (predicate.test(mid)) {
                    r = mid;
                } else {
                    l = mid + 1;
                }
            }
            if (!predicate.test(l)) {
                l++;
            }
            return l;
        }

    }

    static class Randomized {
        public static void shuffle(int[] data) {
            shuffle(data, 0, data.length - 1);
        }

        public static void shuffle(int[] data, int from, int to) {
            to--;
            for (int i = from; i <= to; i++) {
                int s = nextInt(i, to);
                int tmp = data[i];
                data[i] = data[s];
                data[s] = tmp;
            }
        }

        public static int nextInt(int l, int r) {
            return RandomWrapper.INSTANCE.nextInt(l, r);
        }

    }

    static strictfp class MersenneTwisterFast implements Serializable, Cloneable {
        private static final int N = 624;
        private static final int M = 397;
        private static final int MATRIX_A = 0x9908b0df;
        private static final int UPPER_MASK = 0x80000000;
        private static final int LOWER_MASK = 0x7fffffff;
        private static final int TEMPERING_MASK_B = 0x9d2c5680;
        private static final int TEMPERING_MASK_C = 0xefc60000;
        private int[] mt;
        private int mti;
        private int[] mag01;
        private boolean __haveNextNextGaussian;

        public Object clone() {
            try {
                MersenneTwisterFast f = (MersenneTwisterFast) (super.clone());
                f.mt = (int[]) (mt.clone());
                f.mag01 = (int[]) (mag01.clone());
                return f;
            } catch (CloneNotSupportedException e) {
                throw new InternalError();
            } // should never happen
        }

        public MersenneTwisterFast() {
            this(System.currentTimeMillis());
        }

        public MersenneTwisterFast(long seed) {
            setSeed(seed);
        }

        public MersenneTwisterFast(int[] array) {
            setSeed(array);
        }

        public void setSeed(long seed) {
            // Due to a bug in java.util.Random clear up to 1.2, we're
            // doing our own Gaussian variable.
            __haveNextNextGaussian = false;

            mt = new int[N];

            mag01 = new int[2];
            mag01[0] = 0x0;
            mag01[1] = MATRIX_A;

            mt[0] = (int) (seed & 0xffffffff);
            for (mti = 1; mti < N; mti++) {
                mt[mti] =
                        (1812433253 * (mt[mti - 1] ^ (mt[mti - 1] >>> 30)) + mti);
                /* See Knuth TAOCP Vol2. 3rd Ed. P.106 for multiplier. */
                /* In the previous versions, MSBs of the seed affect   */
                /* only MSBs of the array mt[].                        */
                /* 2002/01/09 modified by Makoto Matsumoto             */
                // mt[mti] &= 0xffffffff;
                /* for >32 bit machines */
            }
        }

        public void setSeed(int[] array) {
            if (array.length == 0)
                throw new IllegalArgumentException("Array length must be greater than zero");
            int i, j, k;
            setSeed(19650218);
            i = 1;
            j = 0;
            k = (N > array.length ? N : array.length);
            for (; k != 0; k--) {
                mt[i] = (mt[i] ^ ((mt[i - 1] ^ (mt[i - 1] >>> 30)) * 1664525)) + array[j] + j; /* non linear */
                // mt[i] &= 0xffffffff; /* for WORDSIZE > 32 machines */
                i++;
                j++;
                if (i >= N) {
                    mt[0] = mt[N - 1];
                    i = 1;
                }
                if (j >= array.length) j = 0;
            }
            for (k = N - 1; k != 0; k--) {
                mt[i] = (mt[i] ^ ((mt[i - 1] ^ (mt[i - 1] >>> 30)) * 1566083941)) - i; /* non linear */
                // mt[i] &= 0xffffffff; /* for WORDSIZE > 32 machines */
                i++;
                if (i >= N) {
                    mt[0] = mt[N - 1];
                    i = 1;
                }
            }
            mt[0] = 0x80000000; /* MSB is 1; assuring non-zero initial array */
        }

        public int nextInt(int n) {
            if (n <= 0)
                throw new IllegalArgumentException("n must be positive, got: " + n);

            if ((n & -n) == n)  // i.e., n is a power of 2
            {
                int y;

                if (mti >= N)   // generate N words at one time
                {
                    int kk;
                    final int[] mt = this.mt; // locals are slightly faster
                    final int[] mag01 = this.mag01; // locals are slightly faster

                    for (kk = 0; kk < N - M; kk++) {
                        y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
                        mt[kk] = mt[kk + M] ^ (y >>> 1) ^ mag01[y & 0x1];
                    }
                    for (; kk < N - 1; kk++) {
                        y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
                        mt[kk] = mt[kk + (M - N)] ^ (y >>> 1) ^ mag01[y & 0x1];
                    }
                    y = (mt[N - 1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
                    mt[N - 1] = mt[M - 1] ^ (y >>> 1) ^ mag01[y & 0x1];

                    mti = 0;
                }

                y = mt[mti++];
                y ^= y >>> 11;                          // TEMPERING_SHIFT_U(y)
                y ^= (y << 7) & TEMPERING_MASK_B;       // TEMPERING_SHIFT_S(y)
                y ^= (y << 15) & TEMPERING_MASK_C;      // TEMPERING_SHIFT_T(y)
                y ^= (y >>> 18);                        // TEMPERING_SHIFT_L(y)

                return (int) ((n * (long) (y >>> 1)) >> 31);
            }

            int bits, val;
            do {
                int y;

                if (mti >= N)   // generate N words at one time
                {
                    int kk;
                    final int[] mt = this.mt; // locals are slightly faster
                    final int[] mag01 = this.mag01; // locals are slightly faster

                    for (kk = 0; kk < N - M; kk++) {
                        y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
                        mt[kk] = mt[kk + M] ^ (y >>> 1) ^ mag01[y & 0x1];
                    }
                    for (; kk < N - 1; kk++) {
                        y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
                        mt[kk] = mt[kk + (M - N)] ^ (y >>> 1) ^ mag01[y & 0x1];
                    }
                    y = (mt[N - 1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
                    mt[N - 1] = mt[M - 1] ^ (y >>> 1) ^ mag01[y & 0x1];

                    mti = 0;
                }

                y = mt[mti++];
                y ^= y >>> 11;                          // TEMPERING_SHIFT_U(y)
                y ^= (y << 7) & TEMPERING_MASK_B;       // TEMPERING_SHIFT_S(y)
                y ^= (y << 15) & TEMPERING_MASK_C;      // TEMPERING_SHIFT_T(y)
                y ^= (y >>> 18);                        // TEMPERING_SHIFT_L(y)

                bits = (y >>> 1);
                val = bits % n;
            } while (bits - val + (n - 1) < 0);
            return val;
        }

    }

    static class FastInput {
        private final InputStream is;
        private byte[] buf = new byte[1 << 13];
        private int bufLen;
        private int bufOffset;
        private int next;

        public FastInput(InputStream is) {
            this.is = is;
        }

        private int read() {
            while (bufLen == bufOffset) {
                bufOffset = 0;
                try {
                    bufLen = is.read(buf);
                } catch (IOException e) {
                    bufLen = -1;
                }
                if (bufLen == -1) {
                    return -1;
                }
            }
            return buf[bufOffset++];
        }

        public void skipBlank() {
            while (next >= 0 && next <= 32) {
                next = read();
            }
        }

        public int ri() {
            return readInt();
        }

        public int readInt() {
            int sign = 1;

            skipBlank();
            if (next == '+' || next == '-') {
                sign = next == '+' ? 1 : -1;
                next = read();
            }

            int val = 0;
            if (sign == 1) {
                while (next >= '0' && next <= '9') {
                    val = val * 10 + next - '0';
                    next = read();
                }
            } else {
                while (next >= '0' && next <= '9') {
                    val = val * 10 - next + '0';
                    next = read();
                }
            }

            return val;
        }

    }

    static class RandomWrapper {
        private MersenneTwisterFast random;
        public static final RandomWrapper INSTANCE = new RandomWrapper();

        public RandomWrapper() {
            this(new MersenneTwisterFast());
        }

        public RandomWrapper(MersenneTwisterFast random) {
            this.random = random;
        }

        public RandomWrapper(long seed) {
            this(new MersenneTwisterFast(seed));
        }

        public int nextInt(int l, int r) {
            return random.nextInt(r - l + 1) + l;
        }

    }
}

