using System;
using System.Linq;
using System.Collections.Generic;
using Debug = System.Diagnostics.Trace;
using SB = System.Text.StringBuilder;
using System.Numerics;
using static System.Math;
using Number = System.Int64;
namespace Program {
    public class Solver {
        Random rnd = new Random(0);
        public void Solve() {
            var n = ri;
            var m = ri;
            var X = Enumerate(n, x => rl);
            var Y = Enumerate(m, x => rl);
            var L = new long[n];
            var R = new long[n];
            foreach (var i in Rep(n)) {
                var p = ~Array.BinarySearch(Y, X[i]);
                R[i] = p == m ? -1 : Y[p] - X[i];
                L[i] = p == 0 ? -1 : X[i] - Y[p - 1];
            }
            var xs = L.Concat(new long[] { -1, 0 }).Distinct().OrderBy(x => x).ToList();
            var ys = R.Concat(new long[] { -1, 0 }).Distinct().OrderBy(x => x).ToList();
            var N = xs.Count;
            var K = ys.Count;
            var ev = Enumerate(K, x => new SortedSet<int>());
            foreach (var i in Rep(n)) {
                if (L[i] == -1 || R[i] == -1) continue;
                var l = xs.BinarySearch(L[i]);
                var r = ys.BinarySearch(R[i]);
                Debug.WriteLine($"{l} {r}");
                ev[r].Add(l);
            }
            var dp = new FenwickTree(N);
            dp.Add(1, 1);
            foreach (var events in ev) {
                if (events.Count == 0) continue;
                Debug.WriteLine(dp.Items.AsJoinedString());
                foreach (var x in events.Reverse()) {
                    var sum = dp[x - 1];
                    dp.Add(x, sum);
                }
            }
            Debug.WriteLine(dp.Items.AsJoinedString());
            Console.WriteLine(dp[N]);
        }
        const long INF = 1L << 60;
        int ri => sc.Integer();
        long rl => sc.Long();
        double rd => sc.Double();
        string rs => sc.Scan();
        public IO.StreamScanner sc = new IO.StreamScanner(Console.OpenStandardInput());

        static IEnumerable<int> Rep(int n) => Enumerable.Range(0, n);
        static IEnumerable<int> RRep(int n) => Enumerable.Range(0, n).Reverse();
        static T[] Enumerate<T>(int n, Func<int, T> f) {
            var a = new T[n];
            for (int i = 0; i < a.Length; ++i) a[i] = f(i);
            return a;
        }
        static public void Swap<T>(ref T a, ref T b) { var tmp = a; a = b; b = tmp; }
    }
}
#region main
static class Ex {
    static public string AsString(this IEnumerable<char> ie) { return new string(ie.ToArray()); }
    static public string AsJoinedString<T>(this IEnumerable<T> ie, string st = " ") {
        return string.Join(st, ie);
    }
    static public void Main() {
        Console.SetOut(new Program.IO.Printer(Console.OpenStandardOutput()) { AutoFlush = false });
        var solver = new Program.Solver();
        solver.Solve();
        Console.Out.Flush();
    }
}
#endregion
#region Ex
namespace Program.IO {
    using System.IO;
    using System.Text;
    using System.Globalization;

    public class Printer : StreamWriter {
        public override IFormatProvider FormatProvider => CultureInfo.InvariantCulture;
        public Printer(Stream stream) : base(stream, new UTF8Encoding(false, true)) { }
    }

    public class StreamScanner {
        public StreamScanner(Stream stream) { str = stream; }

        public readonly Stream str;
        private readonly byte[] buf = new byte[1024];
        private int len, ptr;
        public bool isEof = false;

        private byte read() {
            if (isEof) return 0;
            if (ptr >= len) {
                ptr = 0;
                if ((len = str.Read(buf, 0, 1024)) <= 0) {
                    isEof = true;
                    return 0;
                }
            }
            return buf[ptr++];
        }

        public char Char() {
            byte b = 0;
            do b = read(); while ((b < 33 || 126 < b) && !isEof);
            return (char)b;
        }
        public string Scan() {
            var sb = new StringBuilder();
            for (var b = Char(); b >= 33 && b <= 126; b = (char)read()) sb.Append(b);
            return sb.ToString();
        }
        public string ScanLine() {
            var sb = new StringBuilder();
            for (var b = Char(); b != '\n' && b != 0; b = (char)read()) if (b != '\r') sb.Append(b);
            return sb.ToString();
        }
        public long Long() { return isEof ? long.MinValue : long.Parse(Scan()); }
        public int Integer() { return isEof ? int.MinValue : int.Parse(Scan()); }
        public double Double() { return isEof ? double.NaN : double.Parse(Scan(), CultureInfo.InvariantCulture); }
    }
}

#endregion
#region FenwickTree
public class FenwickTree {
    const long M = (long)1e9 + 7;
    int n;
    Number[] bit;
    int max = 1;
    public FenwickTree(int size) {
        n = size; bit = new Number[n + 1];
        while ((max << 1) <= n) max <<= 1;
    }
    /// <summary>sum[a,b]</summary>
    public Number this[int i, int j] { get { return (this[j] + M - this[i - 1]) % M; } }
    /// <summary>sum[0,i]</summary>
    public Number this[int i] { get { Number s = 0; for (; i > 0; i -= i & -i) s = (s + bit[i]) % M; return s; } }
    /// <summary>add v to bit[i]</summary>
    public void Add(int i, Number v) {
        Debug.Assert(i >= 1);
        for (; i <= n; i += i & -i) bit[i] = (bit[i] + v) % M;
    }
    public Number[] Items {
        get {
            var ret = new Number[n + 1];
            for (int i = 0; i < ret.Length; i++)
                ret[i] = this[i, i];
            return ret;
        }
    }
}
#endregion


Measured memory_bytes: 49064