"use strict";
    
const getLcm = (x, y) => {
  return (!x || !y) ? 0 : Math.abs((x * y) / getGcm(x, y));
}

const getGcm = (x, y) => {
  x = Math.abs(x);
  y = Math.abs(y);
  while (y) {
    let t = y;
    y = x % y;
    x = t;
  }
  return x;
}

const main = arg => {
    arg = arg.trim().split("\n");
    const A = parseInt(arg[0].split(" ")[0]);
    const B = parseInt(arg[0].split(" ")[1]);
    const C = parseInt(arg[0].split(" ")[2]);
    const D = parseInt(arg[0].split(" ")[3]);
    
    let lcm = getLcm(C, D);
    
    let temp1 = Math.floor(A / lcm);
    let temp2 = Math.floor(B / lcm);
    
    let temp3 = Math.floor(A / C);
    let temp4 = Math.floor(B / C);
    
    let temp5 = Math.floor(A / D);
    let temp6 = Math.floor(B / D);
    
    console.log(temp4 - temp3)
    console.log(temp6 - temp5)
    
    let step1 = (temp4 + temp6) - temp2;
    let step2 = (temp3 + temp5) - temp1;
    
    let special = 0;
    
    if(A % C === 0 && A % D === 0) {
        special = 3;
    } else if(A % C === 0) {
        special++;
    } else if(A % D === 0) {
        special++;
    }
    
    console.log(((B - A) + 1) - (step1 - (step2 - special)) );
}
main(require('fs').readFileSync('/dev/stdin', 'utf8'));