using Lib;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Text;
using static Lib.OutputLib;
public class Solver
{
    const bool MultiTestCase = false;
    void Solve()
    {
        int n = ri, m = ri;

        var seg = new DualSegTree<long, LongAddGroup>(n + 1);
        for (int i = 0; i <= n; i++) seg.Set(i, (long)i * m);
        for (int i = 1; i <= m; i++)
            for (int j = 1; i * j <= n; j++)
                seg.Apply(i * j, n + 1, -i);
        
        Write(seg.AllGet().Max());
    }

#pragma warning disable CS0162
    public Solver() { if (!MultiTestCase) Solve(); else for (int t = ri; t > 0; t--) Solve(); }
#pragma warning restore CS0162

    const int IINF = 1 << 30;
    const long INF = 1L << 60;
    int ri { [MethodImpl(256)] get => (int)sc.Integer(); }
    long rl { [MethodImpl(256)] get => sc.Integer(); }
    uint rui { [MethodImpl(256)] get => (uint)sc.UInteger(); }
    ulong rul { [MethodImpl(256)] get => sc.UInteger(); }
    double rd { [MethodImpl(256)] get => sc.Double(); }
    string rs { [MethodImpl(256)] get => sc.Scan(); }
    string rline { [MethodImpl(256)] get => sc.Line(); }
    public StreamScanner sc = new StreamScanner(Console.OpenStandardInput());
    void ReadArray(out int[] a, int n) { a = new int[n]; for (int i = 0; i < a.Length; i++) a[i] = ri; }
    void ReadArray(out long[] a, int n) { a = new long[n]; for (int i = 0; i < a.Length; i++) a[i] = rl; }
    void ReadArray<T>(out T[] a, int n, Func<T> read) { a = new T[n]; for (int i = 0; i < a.Length; i++) a[i] = read(); }
    void ReadArray<T>(out T[] a, int n, Func<int, T> read) { a = new T[n]; for (int i = 0; i < a.Length; i++) a[i] = read(i); }
}

static class Program
{
    static public void Main(string[] args)
    {
        SourceExpander.Expander.Expand();
        Console.SetOut(new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false });
        new Solver();
        Console.Out.Flush();
    }
}
#region Expanded by https://github.com/kzrnm/SourceExpander
namespace Lib{public class DualSegTree<F,Op>where Op:struct,IMonoid<F>{protected static readonly Op op=default;public int Length{get;}protected readonly int size,log;protected readonly F[]lz;public DualSegTree(int n){Length=n;size=1;log=0;while(size<Length){size*=2;log++;}lz=new F[size*2];Array.Fill(lz,op.Identity);}[MethodImpl(256)]public void Set(int p,F f){p+=size;for(int i=log;i>0;i--)Push(p>>i);lz[p]=f;}[MethodImpl(256)]public F Get(int p){p+=size;for(int i=log;i>0;i--)Push(p>>i);return lz[p];}[MethodImpl(256)]public F[]AllGet(){for(int i=1;i<size;i++)Push(i);return lz[size..(size+Length)];}[MethodImpl(256)]public void Apply(int p,F f){p+=size;for(int i=log;i>0;i--)Push(p>>i);InnerApply(p,f);}[MethodImpl(256)]public void Apply(int l,int r,F f){if(l>=r)return;l+=size;r+=size;for(int i=log;i>0;i--){if(((l>>i)<<i)!=l)Push(l>>i);if(((r>>i)<<i)!=r)Push((r-1)>>i);}while(l<r){if((l&1)!=0)InnerApply(l++,f);if((r&1)!=0)InnerApply( --r,f);l>>=1;r>>=1;}}[MethodImpl(256)]void Push(int k){InnerApply(2*k,lz[k]);InnerApply(2*k+1,lz[k]);lz[k]=op.Identity;}[MethodImpl(256)]void InnerApply(int k,F f)=>lz[k]=op.Operate(f,lz[k]);}}
namespace Lib{public interface IGroup<T>:IMonoid<T>,IInvertible<T>{}public struct IntAddGroup:IMonoid<int>,IGroup<int>{public int Identity=>0;public int Operate(int x,int y)=>x+y;public int Inverse(int x)=>-x;}public struct LongAddGroup:IMonoid<long>,IGroup<long>{public long Identity=>0;public long Operate(long x,long y)=>x+y;public long Inverse(long x)=>-x;}public struct ModIntAddGroup<T>:IMonoid<StaticModInt<T>>,IGroup<StaticModInt<T>>where T:struct,IStaticMod{public StaticModInt<T>Identity=>0;public StaticModInt<T>Operate(StaticModInt<T>x,StaticModInt<T>y)=>x+y;public StaticModInt<T>Inverse(StaticModInt<T>x)=>-x;}public struct IntPairAddGroup:IMonoid<(int,int)>,IGroup<(int,int)>{public(int,int)Identity=>(0,0);public(int,int)Operate((int,int)x,(int,int)y)=>(x.Item1+y.Item1,x.Item2+y.Item2);public(int,int)Inverse((int,int)x)=>(-x.Item1,-x.Item2);}public struct LongPairAddGroup:IMonoid<(long,long)>,IGroup<(long,long)>{public(long,long)Identity=>(0,0);public(long,long)Operate((long,long)x,(long,long)y)=>(x.Item1+y.Item1,x.Item2+y.Item2);public(long,long)Inverse((long,long)x)=>(-x.Item1,-x.Item2);}}
namespace Lib{public interface IMonoid<T>:IOperation<T>,IIdentity<T>{}public struct IntMinMonoid:IMonoid<int>{public int Identity=>int.MaxValue;public int Operate(int x,int y)=>Math.Min(x,y);}public struct IntMaxMonoid:IMonoid<int>{public int Identity=>int.MinValue;public int Operate(int x,int y)=>Math.Max(x,y);}public struct LongMinMonoid:IMonoid<long>{public long Identity=>long.MaxValue;public long Operate(long x,long y)=>Math.Min(x,y);}public struct LongMaxMonoid:IMonoid<long>{public long Identity=>long.MinValue;public long Operate(long x,long y)=>Math.Max(x,y);}public struct PairMonoid<T1,Op1,T2,Op2>:IMonoid<(T1,T2)>where Op1:struct,IMonoid<T1>where Op2:struct,IMonoid<T2>{public readonly static Op1 op1=default;public readonly static Op2 op2=default;public(T1,T2)Identity=>(op1.Identity,op2.Identity);public(T1,T2)Operate((T1,T2)x,(T1,T2)y)=>(op1.Operate(x.Item1,y.Item1),op2.Operate(x.Item2,y.Item2));}public struct Tuple2Monoid<T,Op>:IMonoid<(T,T)>where Op:struct,IMonoid<T>{public readonly static Op op=default;public(T,T)Identity=>(op.Identity,op.Identity);public(T,T)Operate((T,T)x,(T,T)y)=>(op.Operate(x.Item1,y.Item1),op.Operate(x.Item2,y.Item2));}public struct Tuple3Monoid<T,Op>:IMonoid<(T,T,T)>where Op:struct,IMonoid<T>{public readonly static Op op=default;public(T,T,T)Identity=>(op.Identity,op.Identity,op.Identity);public(T,T,T)Operate((T,T,T)x,(T,T,T)y)=>(op.Operate(x.Item1,y.Item1),op.Operate(x.Item2,y.Item2),op.Operate(x.Item3,y.Item3));}public struct Tuple4Monoid<T,Op>:IMonoid<(T,T,T,T)>where Op:struct,IMonoid<T>{public readonly static Op op=default;public(T,T,T,T)Identity=>(op.Identity,op.Identity,op.Identity,op.Identity);public(T,T,T,T)Operate((T,T,T,T)x,(T,T,T,T)y)=>(op.Operate(x.Item1,y.Item1),op.Operate(x.Item2,y.Item2),op.Operate(x.Item3,y.Item3),op.Operate(x.Item4,y.Item4));}}
namespace Lib{public interface IIdentity<T>{T Identity{get;}}}
namespace Lib{public interface IInvertible<T>{T Inverse(T x);}}
namespace Lib{public interface IOperation<T>{T Operate(T x,T y);}}
namespace Lib{public partial class StreamScanner{public int[][]ReadUnweightedTree(int n,int origin=1){var gr=new List<int>[n];for(int i=0;i<n;i++)gr[i]=new List<int>();for(int i=0;i<n-1;i++){int u=(int)(Integer()-origin);int v=(int)(Integer()-origin);gr[u].Add(v);gr[v].Add(u);}var g=new int[n][];for(int i=0;i<n;i++)g[i]=gr[i].ToArray();return g;}}}
namespace Lib{public partial class StreamScanner{public StreamScanner(Stream stream){str=stream;}private readonly Stream str;private readonly byte[]buf=new byte[1024];private int len,ptr;public bool isEof=false;public bool IsEndOfStream{get{return isEof;}}[MethodImpl(256)]private byte Read(){if(isEof)throw new EndOfStreamException();if(ptr>=len){ptr=0;if((len=str.Read(buf,0,1024))<=0){isEof=true;return 0;}}return buf[ptr++];}[MethodImpl(256)]public char Char(){byte b=0;do b=Read();while(b<33||126<b);return(char)b;}[MethodImpl(256)]public string Line(){var sb=new StringBuilder();for(var b=Char();b!=10&&!isEof;b=(char)Read())sb.Append(b);return sb.ToString();}[MethodImpl(256)]public string Scan(){var sb=new StringBuilder();for(var b=Char();b>=33&&b<=126;b=(char)Read())sb.Append(b);return sb.ToString();}[MethodImpl(256)]public long Integer(){long ret=0;byte b=0;var ng=false;do b=Read();while(b!='-'&&(b<'0'||'9'<b));if(b=='-'){ng=true;b=Read();}for(;true;b=Read()){if(b<'0'||'9'<b)return ng?-ret:ret;else ret=ret*10+b-'0';}}[MethodImpl(256)]public ulong UInteger(){ulong ret=0;byte b=0;do b=Read();while(b<'0'||'9'<b);for(;true;b=Read()){if(b<'0'||'9'<b)return ret;else ret=ret*10+b-'0';}}[MethodImpl(256)]public double Double()=>double.Parse(Scan());}}
namespace Lib{public interface IStaticMod{uint Mod{get;}bool IsPrime{get;}}public readonly struct Mod1000000007:IStaticMod{public uint Mod=>1000000007;public bool IsPrime=>true;}public readonly struct Mod998244353:IStaticMod{public uint Mod=>998244353;public bool IsPrime=>true;}public readonly struct StaticModInt<T>:IEquatable<StaticModInt<T>>where T:struct,IStaticMod{internal readonly uint _v;private static readonly T op=default;public int Value=>(int)_v;public static int Mod=>(int)op.Mod;public static StaticModInt<T>Zero=>default;public static StaticModInt<T>One=>new StaticModInt<T>(1u);[MethodImpl(256)]public static StaticModInt<T>Raw(int v){var u=unchecked((uint)v);return new StaticModInt<T>(u);}[MethodImpl(256)]public StaticModInt(long v):this(Round(v)){}[MethodImpl(256)]public StaticModInt(ulong v):this((uint)(v%op.Mod)){}[MethodImpl(256)]private StaticModInt(uint v)=>_v=v;[MethodImpl(256)]private static uint Round(long v){var x=v%op.Mod;if(x<0)x+=op.Mod;return(uint)x;}[MethodImpl(256)]public static StaticModInt<T>operator ++(StaticModInt<T>v){var x=v._v+1;if(x==op.Mod)x=0;return new StaticModInt<T>(x);}[MethodImpl(256)]public static StaticModInt<T>operator --(StaticModInt<T>v){var x=v._v;if(x==0)x=op.Mod;return new StaticModInt<T>(x-1);}[MethodImpl(256)]public static StaticModInt<T>operator+(StaticModInt<T>lhs,StaticModInt<T>rhs){var v=lhs._v+rhs._v;if(v>=op.Mod)v-=op.Mod;return new StaticModInt<T>(v);}[MethodImpl(256)]public static StaticModInt<T>operator-(StaticModInt<T>lhs,StaticModInt<T>rhs){unchecked{var v=lhs._v-rhs._v;if(v>=op.Mod)v+=op.Mod;return new StaticModInt<T>(v);}}[MethodImpl(256)]public static StaticModInt<T>operator*(StaticModInt<T>lhs,StaticModInt<T>rhs)=>new StaticModInt<T>((uint)((ulong)lhs._v*rhs._v%op.Mod));[MethodImpl(256)]public static StaticModInt<T>operator/(StaticModInt<T>lhs,StaticModInt<T>rhs)=>new StaticModInt<T>((uint)((ulong)lhs._v*Inv(rhs._v)%op.Mod));[MethodImpl(256)]public static StaticModInt<T>operator+(StaticModInt<T>v)=>v;[MethodImpl(256)]public static StaticModInt<T>operator-(StaticModInt<T>v)=>new StaticModInt<T>(v._v==0?0:op.Mod-v._v);[MethodImpl(256)]public static bool operator==(StaticModInt<T>lhs,StaticModInt<T>rhs)=>lhs._v==rhs._v;[MethodImpl(256)]public static bool operator!=(StaticModInt<T>lhs,StaticModInt<T>rhs)=>lhs._v!=rhs._v;[MethodImpl(256)]public static implicit operator StaticModInt<T>(int v)=>new StaticModInt<T>(v);[MethodImpl(256)]public static implicit operator StaticModInt<T>(uint v)=>new StaticModInt<T>((long)v);[MethodImpl(256)]public static implicit operator StaticModInt<T>(long v)=>new StaticModInt<T>(v);[MethodImpl(256)]public static implicit operator StaticModInt<T>(ulong v)=>new StaticModInt<T>(v);[MethodImpl(256)]public static implicit operator long(StaticModInt<T>v)=>v._v;[MethodImpl(256)]public static implicit operator ulong(StaticModInt<T>v)=>v._v;[MethodImpl(256)]public StaticModInt<T>Pow(long n){var x=this;var r=new StaticModInt<T>(1U);if(n<0)(x,n)=(x.Inv(),-n);while(n>0){if((n&1)>0)r*=x;x*=x;n>>=1;}return r;}[MethodImpl(256)]public StaticModInt<T>Inv()=>new StaticModInt<T>(Inv(_v));[MethodImpl(256)]static ulong Inv(ulong x){long u=op.Mod,xu=1,yu=0,v=(long)x,xv=0,yv=1;while(v!=0){long w=SafeMod(u,v);long q=(u-w)/v;long xw=xu-xv*q;long yw=yu-yv*q;u=v;xu=xv;yu=yv;v=w;xv=xw;yv=yw;}return(ulong)(yu<0?yu+op.Mod:yu);}[MethodImpl(256)]static long SafeMod(long x,long m){long r=x%m;if(r<0)r+=m;return r;}[MethodImpl(256)]public override string ToString()=>_v.ToString();[MethodImpl(256)]public string ToString(string format,IFormatProvider formatProvider)=>_v.ToString(format,formatProvider);[MethodImpl(256)]public override bool Equals(object?obj)=>obj is StaticModInt<T>m&&Equals(m);[MethodImpl(256)]public bool Equals(StaticModInt<T>other)=>_v==other._v;[MethodImpl(256)]public override int GetHashCode()=>_v.GetHashCode();}}
namespace Lib{public static class OutputLib{[MethodImpl(256)]public static void WriteJoin<T>(string s,IEnumerable<T>t)=>Console.WriteLine(string.Join(s,t));[MethodImpl(256)]public static void WriteMat<T>(T[,]a,string sep=" "){int sz1=a.GetLength(0),sz2=a.GetLength(1);var b=new T[sz2];for(int i=0;i<sz1;i++){for(int j=0;j<sz2;j++)b[j]=a[i,j];WriteJoin(sep,b);}}[MethodImpl(256)]public static void WriteMat<T>(T[][]a,string sep=" "){for(int i=0;i<a.Length;i++)WriteJoin(sep,a[i]);}[MethodImpl(256)]public static void WriteMat<T>(T[][]a,Func<T,string>map,string sep=" "){for(int i=0;i<a.Length;i++)WriteJoin(sep,a[i].Select(x=>map(x)));}[MethodImpl(256)]public static void Write(object t)=>Console.WriteLine(t.ToString());[MethodImpl(256)]public static void Write(params object[]arg)=>Console.WriteLine(string.Join(" ",arg.Select(x=>x.ToString())));[MethodImpl(256)]public static void Write(string str)=>Console.WriteLine(str);[MethodImpl(256)]public static void WriteFlush(object t){Console.WriteLine(t.ToString());Console.Out.Flush();}[MethodImpl(256)]public static void WriteError(object t)=>Console.Error.WriteLine(t.ToString());[MethodImpl(256)]public static void Flush()=>Console.Out.Flush();[MethodImpl(256)]public static void YN(bool t)=>Console.WriteLine(t?"YES":"NO");[MethodImpl(256)]public static void Yn(bool t)=>Console.WriteLine(t?"Yes":"No");[MethodImpl(256)]public static void yn(bool t)=>Console.WriteLine(t?"yes":"no");[MethodImpl(256)]public static void DeleteLine()=>Console.Write("\x1b[1A\x1b[2K");[MethodImpl(256)]public static void ProgressBar(long now,long total,int blocks=50){int x=(int)((2*now*blocks+1)/(2*total));Console.Write($"\x1b[G[\x1b[42m{string.Concat(Enumerable.Repeat("_",x))}\x1b[0m{string.Concat(Enumerable.Repeat("_",blocks-x))}] : {now} / {total}");}}}
namespace SourceExpander{public class Expander{[Conditional("EXP")]public static void Expand(string inputFilePath=null,string outputFilePath=null,bool ignoreAnyError=true){}public static string ExpandString(string inputFilePath=null,bool ignoreAnyError=true){return "";}}}
#endregion Expanded by https://github.com/kzrnm/SourceExpander