process.stdin.resume();
process.stdin.setEncoding("utf8");

var lines = [];
var reader = require('readline').createInterface({
  input: process.stdin, output: process.stdout
});

reader.on('line', (line) => {
  lines.push(line);
});

reader.on('close', solve);

function solve() {
  let a = lines[0].split(' ');
  const L = parseInt(a[0]);
  const R = parseInt(a[1]);
  const d = parseInt(a[2]);
  let count = 0;

  for(let i = L; i <= R; i++) {
    if(i % d === 0) {
      count++;
    }
  }

  console.log(count);
}