Problem:
Score : 500 points

Problem Statement

Given are N positive integers A_1,...,A_N.

Consider positive integers B_1, ..., B_N that satisfy the following condition.

Condition: For any i, j such that 1 \leq i < j \leq N, A_i B_i = A_j B_j holds.

Find the minimum possible value of B_1 + ... + B_N for such B_1,...,B_N.

Since the answer can be enormous, print the sum modulo (10^9 +7).

Constraints

1 \leq N \leq 10^4

1 \leq A_i \leq 10^6

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N
A_1 ... A_N

Output

Print the minimum possible value of B_1 + ... + B_N for B_1,...,B_N that satisfy the condition, modulo (10^9 +7).

Sample Input 1

3
2 3 4

Sample Output 1

13

Let B_1=6, B_2=4, and B_3=3, and the condition will be satisfied.

Sample Input 2

5
12 12 12 12 12

Sample Output 2

5

We can let all B_i be 1.

Sample Input 3

3
1000000 999999 999998

Sample Output 3

996989508

Print the sum modulo (10^9+7).

Solution in C# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.Collections;
using System.Collections.Generic;
using System.IO;
using System.Linq;

class Program
{
    static void Main(string[] args)
    {
        var sw = new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false };
        Console.SetOut(sw);
        Solve();
        Console.Out.Flush();
    }
    static void Solve()
    {
        var N = sc.ReadInt();
        var A = sc.ReadIntArray(N);
        var sieve = new SieveOfEratosthenes((int)1e6);
        var lcmcount = new int[(int)1e6+1];
        foreach (var a in A)
        {
            foreach (var tup in sieve.PrimeFactorsTup(a))
            {
                var p = tup.Item1;
                var count = tup.Item2;
                lcmcount[p] = Math.Max(lcmcount[p], count);
            }
        }
        ModInt lcm = 1;
        for (int p = 2; p < lcmcount.Length; p++)
        {
            lcm *= ModInt.Pow(p, lcmcount[p]);
        }
        ModInt ans = 0;
        foreach (var a in A)
        {
            ans += lcm / a;
        }
        Console.WriteLine(ans);
    }
    static Scanner sc = new Scanner();

    class SieveOfEratosthenes
    {
        public int[] Table;
        public SieveOfEratosthenes(int max)
        {
            CreateTable(max);
        }
        // n以下の数について、最小素因数を記録した表を生成する
        private void CreateTable(int n)
        {
            Table = Enumerable.Range(0, n + 1).ToArray();
            if (n <= 3) return;
            // 2の倍数の最小素因数は2
            for (int i = 2; i <= n; i += 2) Table[i] = 2;
            // 3以上の奇数について最小素因数を記録する
            for (int p = 3; p * p <= n; p += 2)
            {
                // 奇数pがp未満の数の倍数である場合は無視
                if (Table[p] < p) continue;
                // 素数pの倍数を記録
                for (int x = p; x <= n; x += p)
                {
                    Table[x] = p;
                }
            }
        }
        // 最小素因数表を使って素因数分解を行う
        public List<int> PrimeFactors(int n)
        {
            var res = new List<int>();
            while (Table[n] != 1)
            {
                res.Add(Table[n]);
                n /= Table[n];
            }
            return res;
        }
        // 素因数を(p, 個数)のペアで返す
        public List<Tuple<int, int>> PrimeFactorsTup(int n)
        {
            var prev = 0;
            var count = 0;
            var res = new List<Tuple<int, int>>();
            if (n <= 1) return res;
            foreach (var p in PrimeFactors(n))
            {
                if (prev != p)
                {
                    if (count > 0) res.Add(Tuple.Create(prev, count));
                    count = 1;
                }
                else count++;
                prev = p;
            }
            res.Add(Tuple.Create(prev, count));
            return res;
        }
        // 素数判定
        public bool IsPrime(int n)
        {
            return Table[n] == n;
        }
    }

    public struct ModInt
    {
        public const long Mod = (int)1e9 + 7;
        public long num;
        public ModInt(long n) { num = n; }
        public override string ToString() { return num.ToString(); }
        public static ModInt operator +(ModInt l, ModInt r) { l.num += r.num; if (l.num >= Mod) l.num -= Mod; return l; }
        public static ModInt operator -(ModInt l, ModInt r) { l.num -= r.num; if (l.num < 0) l.num += Mod; return l; }
        public static ModInt operator *(ModInt l, ModInt r) { return new ModInt(l.num * r.num % Mod); }
        public static ModInt operator /(ModInt l, ModInt r) { return l * Inverse(r); }
        public static implicit operator ModInt(long n) { n %= Mod; if (n < 0) n += Mod; return new ModInt(n); }
        public static ModInt Pow(ModInt v, long k) { return Pow(v.num, k); }
        public static ModInt Pow(long v, long k)
        {
            long ret = 1;
            for (k %= Mod - 1; k > 0; k >>= 1, v = v * v % Mod)
                if ((k & 1) == 1) ret = ret * v % Mod;
            return new ModInt(ret);
        }
        public static ModInt Inverse(ModInt v) { return Pow(v, Mod - 2); }
        private static List<ModInt> Facs = new List<ModInt> { 1 };
        private static List<ModInt> iFacs = new List<ModInt> { 1 };
        public static ModInt Fac(int n)
        {
            for (int i = Facs.Count; i <= n; i++)
            {
                Facs.Add(i * Facs[i - 1]);
                iFacs.Add(Inverse(Facs[i]));
            }
            return Facs[n];
        }
        public static ModInt iFac(int n)
        {
            Fac(n);
            return iFacs[n];
        }
        public static ModInt nCr(int n, int r)
        {
            if (n < r) return 0;
            if (n == r) return 1;
            if (n > (int)1e6) return nCrLoop(n, r);
            return Fac(n) * iFac(r) * iFac(n - r);
        }
        static ModInt nCrLoop(long n, long r)
        {
            ModInt num = 1;
            for (long i = 1; i <= r; i++)
            {
                num = num * (n - i + 1) / i;
            }
            return num;
        }
        public static ModInt nHr(int n, int r)
        {
            return nCr(n + r - 1, r);
        }
    }
}
class Scanner
{
    string[] S = new string[0];
    int Index = 0;
    char[] Separators = new char[] { ' ' };

    public string Next()
    {
        if (this.Index < this.S.Length) return this.S[this.Index++];
        var line = "";
        while (line == "") line = Console.ReadLine();
        this.S = line.Split(this.Separators, StringSplitOptions.RemoveEmptyEntries);
        if (this.S.Length == 0) return this.Next();
        this.Index = 0;
        return this.S[this.Index++];
    }
    public string ReadStr()
    {
        return this.Next();
    }
    public char ReadChar()
    {
        return this.Next()[0];
    }
    public int ReadInt()
    {
        return int.Parse(this.Next());
    }
    public uint ReadUInt()
    {
        return uint.Parse(this.Next());
    }
    public long ReadLong()
    {
        return long.Parse(this.Next());
    }
    public double ReadDouble()
    {
        return double.Parse(this.Next());
    }
    public Tuple<int, int> ReadTup(int add = 0)
    {
        return Tuple.Create(this.ReadInt() + add, this.ReadInt() + add);
    }
    public Tuple<long, long> ReadTupLong(int add = 0)
    {
        return Tuple.Create(this.ReadLong() + add, this.ReadLong() + add);
    }
    public Tuple<int, int, int> ReadTup3(int add = 0)
    {
        return Tuple.Create(this.ReadInt() + add, this.ReadInt() + add, this.ReadInt() + add);
    }
    public Tuple<int, int, int, int> ReadTup4(int add = 0)
    {
        return Tuple.Create(this.ReadInt() + add, this.ReadInt() + add, this.ReadInt() + add, this.ReadInt() + add);
    }
    public int[] ReadIntArray(int n)
    {
        var array = new int[n];
        for (int i = 0; i < array.Length; i++)
        {
            array[i] = this.ReadInt();
        }
        return array;
    }
    public long[] ReadLongArray(int n)
    {
        var array = new long[n];
        for (int i = 0; i < array.Length; i++)
        {
            array[i] = this.ReadLong();
        }
        return array;
    }
    public double[] ReadDoubleArray(int n)
    {
        var array = new double[n];
        for (int i = 0; i < array.Length; i++)
        {
            array[i] = this.ReadDouble();
        }
        return array;
    }
    public char[] ReadCharArray(int n)
    {
        var array = new char[n];
        for (int i = 0; i < array.Length; i++)
        {
            array[i] = this.ReadChar();
        }
        return array;
    }
    public string[] ReadStrArray(int n)
    {
        var array = new string[n];
        for (int i = 0; i < array.Length; i++)
        {
            array[i] = this.ReadStr();
        }
        return array;
    }
    public Tuple<long, long>[] ReadTupLongArray(int n, int add = 0)
    {
        var array = new Tuple<long, long>[n];
        for (int i = 0; i < n; i++)
        {
            array[i] = this.ReadTupLong(add);
        }
        return array;
    }
    public Tuple<int, int>[] ReadTupArray(int n, int add = 0)
    {
        var array = new Tuple<int, int>[n];
        for (int i = 0; i < n; i++)
        {
            array[i] = this.ReadTup(add);
        }
        return array;
    }
    public Tuple<int, int, int>[] ReadTup3Array(int n, int add = 0)
    {
        var array = new Tuple<int, int, int>[n];
        for (int i = 0; i < n; i++)
        {
            array[i] = this.ReadTup3(add);
        }
        return array;
    }
    public Tuple<int, int, int, int>[] ReadTup4Array(int n, int add = 0)
    {
        var array = new Tuple<int, int, int, int>[n];
        for (int i = 0; i < n; i++)
        {
            array[i] = this.ReadTup4(add);
        }
        return array;
    }
}