function Main(input) {
	const min = input.split("\n")[0].split(" ")[0]
	const max = input.split("\n")[0].split(" ")[1]
	const d = input.split("\n")[0].split(" ")[2]
//     const min = input.split(" ")[0]
// 	const max = input.split(" ")[1]
// 	const d = input.split(" ")[2]
    let count = 0;
    for (let i = Number(min); i < Number(max); i++) {
        if(i % d === 0) {
	        count += 1;
	    }
    }
    if(min === d) {
        count +=1;
    }
	console.log(count);
}
Main(require("fs").readFileSync("/dev/stdin", "utf8"));