'use strict'
const main = (input) => {
  const arr = input.split(' ').map(v => Number(v))
  
  let cnt = 0;
  for (let i=arr[0]; i<=arr[1]; i++) {
    if (i % arr[2] === 0) cnt++
  }
  console.log(cnt)
}
main(require("fs").readFileSync("/dev/stdin", "utf8"))