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>
#include <boost/multiprecision/cpp_int.hpp>
#include <boost/multiprecision/cpp_dec_float.hpp>
using namespace std;
typedef long long ll;

namespace mp = boost::multiprecision;
using Bint = mp::cpp_int;
using Real = mp::number<mp::cpp_dec_float<1024>>;

#define INCANT cin.tie(0), ios::sync_with_stdio(false), cout << fixed << setprecision(20)
#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define rep(i,n) FOR(i,0,n)
#define all(x) (x).begin(),(x).end()
#define out(a) cout << a << endl
#define PRINT(V) for (auto v : (V)) cout << v << " "

const int MOD = 1000000007;
const double PI = acos(-1.0);

void solve() {
    int L, R, d;
    cin >> L >> R >> d;
    int count=0;
    FOR(i, L, R+1){
        if(i%d==0) count++;
    }
    out(count);
}
int main() {
    INCANT;
    solve();
    return 0;
}