'use strict'

function main(input) {
    let l = Number(input.split('\n')[0].split(' ')[0]);
    let r = Number(input.split('\n')[0].split(' ')[1]);
    let d = Number(input.split('\n')[0].split(' ')[2]);

    let ans = 0;
    for (let i = l; i <= r; i++) {
        if (i%d===0) {
            ans++;
        }
    }
    console.log(ans);
}

main(require('fs').readFileSync('/dev/stdin', 'utf8'));