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)

/********** Raaghav Raaj (cf: raaghavraaj, cc: mothercoder27) *************/
#include<bits/stdc++.h>
using namespace std;
#define fast cin.tie(NULL); cout.tie(NULL); ios_base::sync_with_stdio(false);
#pragma optimize("-O3")

// #ifndef LOCAL
// #include "trace.h"
// #else
// #define trace(args...)
// #endif

#define int long long
#define vi vector<int>
#define vc vector<char>
#define pi pair<int, int>
#define pii pair<pi,int>
#define rep(i,a,b) for(int i=a; i<b; i++)
#define F first
#define S second
#define PB push_back
#define MP make_pair
#define sp " "
#define endl '\n'
#define all(v) v.begin(), v.end()
#define debug(data) for(auto it: data) cout<<it<<sp;
#define yes cout<<"YES"<<endl
#define no cout<<"NO"<<endl

const int sz = 1e9 + 7;
int gcd(int n, int m) {
	while (n) swap(n, m), n %= m;
	return m;
}

int power(int a, int b) {
	a %= sz;
	int res = 1;
	while (b) {
		if (b & 1) res = (res * a) % sz;
		a = (a * a) % sz;
		b >>= 1;
	}
	return res;
}

int modInverse(int a) { //sz must be prime
	return power(a, sz - 2);
}

void solve() {
	int A, B, M; cin >> A >> B >> M;
	if (A % M == 0)
	{cout << (B / M) - (A / M) + 1 << endl; return;}

	// A is not divisible by M
	cout << (B / M) - (A / M) << endl;
}

int32_t main() {

	fast;
	int T = 1;
	// cin >> T;
	rep(i, 1, T + 1) {
		// cout << "Case #" << i << ": ";
		solve();
	}
}