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 <iostream>
#include <cmath>
using namespace std;
 
int main(){
  int L,R,D;
  cin >> L >> R >> D;
  int ans = 0;
  if(L % D == 0 && R % D == 0){
    ans += 2;
    ans += floor( (double)(R-L-1)/(double)(D) );
  } else if(R % D == 0){
    ans++;
    ans+= floor( (double)(R-L)/(double)(D) );
  } else if(L % D == 0){
    ans++;
    ans+= floor( (double)(R-L)/(double)(D) );
  } else {
    ans = floor( (double)(R-L+1)/(double)(D) );
  }
  cout << ans << endl;

}