console.log((args=>{
  const [L,R,d] = args.trim().split(' ').map(v=>v|0);
  let count = 0;
  for ( let i = L; i <= R; i++ ) {
    if ( i % d === 0 ) count++;
  }
  return `${count}`;
})(require('fs').readFileSync('/dev/stdin', 'utf8')));
