Problem:
Score : 100 points

Problem Statement

How many multiples of d are there among the integers between L and R (inclusive)?

Constraints

All values in input are integers.

1 \leq L \leq R \leq 100

1 \leq d \leq 100

Input

Input is given from Standard Input in the following format:

L R d

Output

Print the number of multiples of d among the integers between L and R (inclusive).

Sample Input 1

5 10 2

Sample Output 1

3

Among the integers between 5 and 10, there are three multiples of 2: 6, 8, and 10.

Sample Input 2

6 20 7

Sample Output 2

2

Among the integers between 6 and 20, there are two multiples of 7: 7 and 14.

Sample Input 3

1 100 1

Sample Output 3

100

Solution in C++ (GCC 9.2.1) (judge verdict: Accepted)

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define endl "\n"
const int dx[] = { -1 , -1 , -1 , 0 , 0 , 0 , 1 , 1 , 1 };
const int dy[] = { -1 , 0 , 1 , -1 , 0 , 1 , -1 , 0 , 1 };
const ll integer = pow(2, 32) - 1; // 4294967295
#define N 8010000
#define TC int t;cin>>t;for(int T=1;T<=t;T++)
#define mod 1000000007
#define PI acos(-1)
#define all(x) (x).begin(),(x).end()
#define rall(x) (x).rbegin(),(x).rend()
void AIA() { ios::sync_with_stdio(0); cin.tie(0); cout.tie(0); }
bool isprime(ll n) {
	for (ll i = 2; i * i <= n; i++) {
		if (n % i == 0)return 0;
	}
	return (n!=1);
}

/*
 _____________              __                ___        ___       ___________________________     ____        ____
|             |            /\ \              |   |      |   |     |                           |    \   \      /   /
|   __________|           / /\ \             |   |      |   |     |      _____      _____     |     \   \    /   /
|  |                     / /  \ \            |   |      |   |     |     |     |    |     |    |      \   \  /   /
|  |                    / /    \ \           |   |      |   |     |     |     |    |     |    |       \   \/   /
|  |______             / /      \ \          |   |______|   |     |     |     |    |     |    |        \      /
|         |           / /        \ \         |              |     |     |     |    |     |    |         \    /
|   ______|          / /          \ \        |    ______    |     |     |     |    |     |    |          |  |
|  |                / /============\ \       |   |      |   |     |     |     |    |     |    |          |  |
|  |               / /==============\ \      |   |      |   |     |     |     |    |     |    |          |  |
|  |              / /                \ \     |   |      |   |     |     |     |    |     |    |          |  |
|  |             / /                  \ \    |   |      |   |     |     |     |    |     |    |          |  |
|__|            /_/                    \_\   |___|      |___|     |_____|     |____|     |____|          |__|

										  <<<<<<<<<<< NEVER GIVE UP !! >>>>>>>>>>>
										<<<<<<<< YOU CAN DO IT IF YOU WANT !! >>>>>>>>
										 <<<<<<<<< BELIEVE IN YOURSELF !! >>>>>>>>>

*/
int main() {
	//cout << fixed << setprecision(9);
	//freopen("stand.in","r",stdin);
	//freopen("stand.out","w",stdout);
	AIA();
	int l,r,d;
	cin>>l>>r>>d;
	int c = 0;
	for(int i = l ; i<= r;i++){
		if(i%d==0){
			c++;
		}
	}
	cout<<c;
	return 0;
}