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)

#pragma GCC optimize("Ofast")   //Comment optimisations for interactive problems (use endl)
#pragma GCC target("avx,avx2,fma")
#pragma GCC optimization ("unroll-loops")
#include<bits/stdc++.h>

using namespace std;

#define  fastio         ios:: sync_with_stdio(0);cin.tie(0);cout.tie(0);cout<<fixed;cout<<setprecision(10);
#define  randomINIT     mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());
#define  foo(i,a,n)     for(ll i = (a); i <= n; i++)
#define  frr(i,a,n)     for(ll i = (a); i >= n; i--)
#define  fo(i,n)        for(ll i = 0; i < n; i++)
#define  all(x)         (x).begin(),(x).end()
#define  mset(x,val)    memset(x,val,sizeof(x))
#define  newl           cout<<"\n"
#define  pb             push_back
#define  mp             make_pair
#define  s              second
#define  f              first
#define  dline          cerr<<"///REACHED///\n";
#define  deb1(x)        cerr<<#x<<" = "<<x<<'\n';
#define  deb2(x,y)      cerr<<'['<<#x<<','<<#y<<"] = "<<'['<<x<<','<<y<<']'<<'\n';
#define  deb3(x,y,z)    cerr<<'['<<#x<<','<<#y<<','<<#z<<"] = "<<'['<<x<<','<<y<<','<<z<<']'<<'\n';

typedef  long long             ll;
typedef  long double           ld;
typedef  pair<ll,ll>           pll;
typedef  vector<ll>            vll;
typedef  vector<pll>           vpll;

const ll   MOD   =  1e+9+7;
const ll   INF   =  0x7f7f7f7f7f7f7f7f;
const int  INFi  =  0x7f7f7f7f;
const ll   MAXN  =  1e+5+7;

vll adj[MAXN];ll visit[MAXN]={};
int dx8[]={0,1,1,1,0,-1,-1,-1}, dy8[]={1,1,0,-1,-1,-1,0,1};
int dx4[]={0,1,0,-1}, dy4[]={1,0,-1,0};

//<<-----Declare Variable Here------->>//
int t=1;
ll n;
//<<-----Implement Functions Here---->>//


//<<-----Start of Main--------------->>//
void MAIN(){
		ll l,r,d;
		cin>>l>>r>>d;
		cout<<r/d-(l-1)/d<<endl;
}

int main(){
	fastio;randomINIT;

	//cin>>t;
	while(t--){
		MAIN();
	}

    #ifndef ONLINE_JUDGE
    cout<<"\nTime Elapsed: " << 1.0*clock() / CLOCKS_PER_SEC << " sec\n";
    #endif
}