const input = require("fs").readFileSync("/dev/stdin", "utf8")

;(input => {

    const lines = input.split('\n')
    const [L, R, d] = lines[0].split(" ").map(Number)

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

    console.log(count)

})(input)
