Problem:
Score : 300 points

Problem Statement

You are given four integers A, B, C, and D. Find the number of integers between A and B (inclusive) that can be evenly divided by neither C nor D.

Constraints

1\leq A\leq B\leq 10^{18}

1\leq C,D\leq 10^9

All values in input are integers.

Input

Input is given from Standard Input in the following format:

A B C D

Output

Print the number of integers between A and B (inclusive) that can be evenly divided by neither C nor D.

Sample Input 1

4 9 2 3

Sample Output 1

2

5 and 7 satisfy the condition.

Sample Input 2

10 40 6 8

Sample Output 2

23

Sample Input 3

314159265358979323 846264338327950288 419716939 937510582

Sample Output 3

532105071133627368

Solution in JavaScript (node.js v5.12) (judge verdict: Wrong Answer)

function lcm(a,b) {
    var g = (n, m) => m ? g(m, n % m) : n
    return a * b / g(a, b)
}
function Main(input){
  input = input.split("\n");
  inputStr = input[0].split(" ");
  var A = Number.parseInt(inputStr[0]);
  var B = Number.parseInt(inputStr[1]);
  var C = Number.parseInt(inputStr[2]);
  var D = Number.parseInt(inputStr[3]);
  var lcm_val = lcm(D,C);
  //変数を定義
  var cnt = 0;
  //計算を実施
  cnt = Math.floor(B/C) - Math.floor((A-1)/C);
  cnt += Math.floor(B/D) - Math.floor((A-1)/D);
  cnt -= Math.floor(B/lcm_val) - Math.floor((A-1)/lcm_val);
  console.log(B-(A-1)-cnt);
}
Main(require("fs").readFileSync("/dev/stdin", "utf8"));