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)

//  Author : Amit Kumar 
//  Date   : Saturday 11 July 2020 05:35:34 PM IST

#include <bits/stdc++.h>
using namespace std;
using namespace std::chrono;
#define int int64_t

signed main(void){
#ifdef HELL_JUDGE
    freopen("input","r",stdin);
    freopen("output","w",stdout);
    freopen("error","w",stderr);
#endif 
    ios::sync_with_stdio(false); // FLUSH THE STREAM IF USING puts / printf / scanf/
    cin.tie(nullptr);            // DISABLE FOR INTERACTIVE PROBLEMS
    cout.tie(nullptr);           //
#ifdef HELL_JUDGE
    auto INITIAL_TIME = high_resolution_clock::now();
#endif 
    int l , r , d; 
    cin >> l >> r >> d; 
    int counter{};
    for(int i=1; i<123; ++i){
        counter += (l <= d * i && d * i <= r);
    }
    cout << counter << '\n'; 
#ifdef HELL_JUDGE
    auto FINAL_TIME = high_resolution_clock::now();
    cout << "Time : "
         << duration_cast<milliseconds>(FINAL_TIME-INITIAL_TIME).count() 
         << " ms" << '\n'; 
#endif 
    return 0;
}