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 Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.io.*;
import java.util.*;

@SuppressWarnings("unused")
public class Main {
    FastScanner in;
    PrintWriter out;
    int MOD = (int)1e9+7;
    long ceil(long a, long b){return (a + b - 1) / b;}
    long gcd(long a, long b){return b == 0 ? a : gcd(b, a % b);}
    long lcm(long a, long b){return a / gcd(a, b) * b;}
    
    void solve(){
        int MAX = (int)1e6;
        int N = in.nextInt();
        int[] A = in.nextIntArray(N);
        
        Sieve sieve = new Sieve();
        int[] ex = new int[MAX+1];
        for(int i = 0; i < N; i++){
            ArrayList<int[]> pf = sieve.primeFactor(A[i]);
            for(int[] e : pf){
                int p = e[0], cnt = e[1];
                ex[p] = Math.max(ex[p], cnt);
            }
        }
        long lcm = 1;
        for(int i = 2; i <= MAX; i++){
            lcm *= ModCalculator.modPow(i, ex[i], MOD);
            lcm %= MOD;
        }
        
        long sum = 0;
        for(int i = 0; i < N; i++){
            sum += (lcm * ModCalculator.modMultiInv(A[i], MOD)) % MOD;
            sum %= MOD;
        }
        out.println(sum);
    }
    
    class Sieve{
        int MAX;
        int[] f;
        ArrayList<Integer> primes;
        
        public Sieve(){
            this((int)1e6);
        }
        
        public Sieve(int m){
            this.MAX = m;
            f = new int[MAX+1];
            primes = new ArrayList<>();
            f[0] = f[1] = -1;
            for(int i = 2; i <= MAX; i++){
                if(f[i] != 0) continue;
                primes.add(i);
                f[i] = i;
                if((long)i*i > MAX) continue;
                for(int j = i*i; j <= MAX; j += i){
                    if(f[j] == 0) f[j] = i;
                }
            }
        }
        
        boolean isPrime(int x){ return f[x] == x;}
        
        ArrayList<Integer> factorList(int x){
            ArrayList<Integer> res = new ArrayList<>();
            while(x != 1){
                res.add(f[x]);
                x /= f[x];
            }
            return res;
        }
        
        ArrayList<int[]> primeFactor(int x){
            ArrayList<Integer> fl = factorList(x);
            ArrayList<int[]> res = new ArrayList<>();
            if(fl.size() == 0){ return res;}
            res.add(new int[]{fl.get(0), 0});
            for(int p : fl){
                if(res.get(res.size()-1)[0] == p){
                    res.get(res.size()-1)[1]++;
                }else{
                    res.add(new int[]{p, 1});
                }
            }
            return res;
        }
    }
    
    static class ModCalculator{
        //引数の最大値、MOD
        private final int MAX_FAC, MOD;
        //階乗・階乗の逆元・積の逆元のテーブル
        private long[] fact, factInv, inv;
        
        public ModCalculator(){
            this(510000, (int)1e9+7);
        }
        
        public ModCalculator(int max, int mod){
            MAX_FAC = max; MOD = mod;
            init();
        }
        
        //テーブルの初期化
        private void init(){
            fact = new long[MAX_FAC+1];
            factInv = new long[MAX_FAC+1];
            inv = new long[MAX_FAC+1];
            fact[0] = factInv[0] = inv[0] = fact[1] = factInv[1] = inv[1] = 1;
            for (int i = 2; i <= MAX_FAC; ++i) {
                fact[i] = fact[i - 1] * i % MOD;
                inv[i] = MOD - (MOD / i) * inv[(int) (MOD % i)] % MOD;
                factInv[i] = factInv[i - 1] * inv[i] % MOD;
            }
        }
        
        //nPk % MOD
        public long modPerm(int n, int k){
            return (n >= k) ? fact[n] * factInv[n - k] % MOD : 0;
        }
        
        //nCk % MOD
        public long modComb(int n, int k){
            return (n >= k) ? fact[n] * factInv[k] % MOD * factInv[n - k] % MOD : 0;
        }
        
        //n! % MOD
        public long modFact(int n){
            return fact[n];
        }
        
        //(n!)^-1 % MOD
        public long modFactInv(int n){
            return factInv[n];
        }
        
        //n^-1 % MOD
        public long modMultiInv(int n){
            return inv[n];
        }
        
        //n^-1 % MOD をlog(MOD)で計算
        public static long modMultiInv(long a, int mod){
            return modPow(a, mod-2, mod);
        }
        
        //a^b % MOD をlog(b)で計算
        public static long modPow(long a, long b, int mod){
            long res = 1;
            while(b > 0){
                if((b & 1) == 1) res = (res * a) % mod;
                a = (a * a) % mod;
                b = b >> 1;
            }
            return res;
        }
    }
    
    public static void main(String[] args) {
        new Main().m();
    }
    
    private void m() {
        in = new FastScanner(System.in);
        out = new PrintWriter(System.out);
        /*
        try {
            String path = "input.txt";
            out = new PrintWriter(new BufferedWriter(new FileWriter(new File(path))));
        }catch (IOException e){
            e.printStackTrace();
        }
        */
        solve();
        out.flush();
        in.close();
        out.close();
    }
    
    static class FastScanner {
        private Reader input;
        
        public FastScanner() {this(System.in);}
        public FastScanner(InputStream stream) {this.input = new BufferedReader(new InputStreamReader(stream));}
        public void close() {
            try {
                this.input.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        
        public int nextInt() {return (int) nextLong();}
        
        public long nextLong() {
            try {
                int sign = 1;
                int b = input.read();
                while ((b < '0' || '9' < b) && b != '-' && b != '+') {
                    b = input.read();
                }
                if (b == '-') {
                    sign = -1;
                    b = input.read();
                } else if (b == '+') {
                    b = input.read();
                }
                long ret = b - '0';
                while (true) {
                    b = input.read();
                    if (b < '0' || '9' < b) return ret * sign;
                    ret *= 10;
                    ret += b - '0';
                }
            } catch (IOException e) {
                e.printStackTrace();
                return -1;
            }
        }
        
        public double nextDouble() {
            try {
                double sign = 1;
                int b = input.read();
                while ((b < '0' || '9' < b) && b != '-' && b != '+') {
                    b = input.read();
                }
                if (b == '-') {
                    sign = -1;
                    b = input.read();
                } else if (b == '+') {
                    b = input.read();
                }
                double ret = b - '0';
                while (true) {
                    b = input.read();
                    if (b < '0' || '9' < b) break;
                    ret *= 10;
                    ret += b - '0';
                }
                if (b != '.') return sign * ret;
                double div = 1;
                b = input.read();
                while ('0' <= b && b <= '9') {
                    ret *= 10;
                    ret += b - '0';
                    div *= 10;
                    b = input.read();
                }
                return sign * ret / div;
            } catch (IOException e) {
                e.printStackTrace();
                return Double.NaN;
            }
        }
        
        public char nextChar() {
            try {
                int b = input.read();
                while (Character.isWhitespace(b)) {
                    b = input.read();
                }
                return (char) b;
            } catch (IOException e) {
                e.printStackTrace();
                return 0;
            }
        }
        
        public String nextStr() {
            try {
                StringBuilder sb = new StringBuilder();
                int b = input.read();
                while (Character.isWhitespace(b)) {
                    b = input.read();
                }
                while (b != -1 && !Character.isWhitespace(b)) {
                    sb.append((char) b);
                    b = input.read();
                }
                return sb.toString();
            } catch (IOException e) {
                e.printStackTrace();
                return "";
            }
        }
        
        public String nextLine() {
            try {
                StringBuilder sb = new StringBuilder();
                int b = input.read();
                while (b != -1 && b != '\n') {
                    sb.append((char) b);
                    b = input.read();
                }
                return sb.toString();
            } catch (IOException e) {
                e.printStackTrace();
                return "";
            }
        }
        
        public int[] nextIntArray(int n) {
            int[] res = new int[n];
            for (int i = 0; i < n; i++) {
                res[i] = nextInt();
            }
            return res;
        }
        
        public int[] nextIntArrayDec(int n) {
            int[] res = new int[n];
            for (int i = 0; i < n; i++) {
                res[i] = nextInt() - 1;
            }
            return res;
        }
        
        public int[] nextIntArray1Index(int n) {
            int[] res = new int[n + 1];
            for (int i = 0; i < n; i++) {
                res[i + 1] = nextInt();
            }
            return res;
        }
        
        public long[] nextLongArray(int n) {
            long[] res = new long[n];
            for (int i = 0; i < n; i++) {
                res[i] = nextLong();
            }
            return res;
        }
        
        public long[] nextLongArrayDec(int n) {
            long[] res = new long[n];
            for (int i = 0; i < n; i++) {
                res[i] = nextLong() - 1;
            }
            return res;
        }
        
        public long[] nextLongArray1Index(int n) {
            long[] res = new long[n + 1];
            for (int i = 0; i < n; i++) {
                res[i + 1] = nextLong();
            }
            return res;
        }
        
        public double[] nextDoubleArray(int n) {
            double[] res = new double[n];
            for (int i = 0; i < n; i++) {
                res[i] = nextDouble();
            }
            return res;
        }
    }
}