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 rep(_,a,b) for(int _=a;_<b;_++)
#define per(_,a,b) for(int _=b-1;_>=a;_--)
#define pii pair<int,int>
#define fi first
#define se second
#define pb push_back
typedef long long ll;

int main()
{
    int l,r,d,ans=0;
    scanf("%d%d%d",&l,&r,&d);
    rep(i,l,r+1){
        if(i%d==0) ans++;
    }
    printf("%d",ans);
}