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 int ll
typedef long long ll;

typedef pair<int, int> pii;
typedef pair<ll,ll> pll;

typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<pii> vpii;
typedef vector<pll> vpll;

#define FOR(i, a, b) for (int i=a; i<(b); i++)
#define F0R(i, a) for (int i=0; i<(a); i++)
#define FORd(i,a,b) for (int i = (b)-1; i >= a; i--)
#define F0Rd(i,a) for (int i = (a)-1; i >= 0; i--)

#define ALL(s) (s).begin(),(s).end()
#define ALLn(s,n) s,s+n
#define F first
#define S second
#define pb push_back
#define tc(t) int t; cin >> t; while(t--)
#define _ ios_base::sync_with_stdio(false); cin.tie(NULL);
#define D1(x) { cerr << " [" << #x << ": " << x << "]\n"; }
#define D2(x) { cerr << " [" << #x << ": "; for(auto it:x) cerr << it << " "; cerr << "]\n"; }

const ll MOD = 1e9 + 7;
const ll MAXN = 1e6 + 7;
const ll INF = LONG_LONG_MAX;

void solve() {
	int l,r,d;
	cin >> l >> r >> d;

	int cnt = 0;
	FOR(i,l,r+1) {
		if(i%d == 0) cnt++;
	}

	cout << cnt << '\n';
}

int32_t main() {_
	
#ifndef ONLINE_JUDGE
	freopen("in", "r", stdin);
	freopen("out", "w", stdout);
#endif

	// tc(t)
		solve();
	cerr << "[ Time : " << (float)clock() / CLOCKS_PER_SEC << " secs ]" << endl;
}