function main(input) {
  let args = input.split(/\s/);
  let result = 0;
  for (let i = args[0] * 1;i <= args[1];i++) {
    if (i % args[2] === 0) {
      result++;
    }
  }
  console.log(result);
}
main(require('fs').readFileSync('/dev/stdin', 'utf8'));