#define _USE_MATH_DEFINES
#define _SILENCE_CXX17_C_HEADER_DEPRECATION_WARNING
#define _SILENCE_ALL_CXX17_DEPRECATION_WARNINGS
#define _CRT_SECURE_NO_WARNINGS
//#include <bits/stdc++.h>

#include <cstdio>
#include <cmath>
#include <algorithm>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <bitset>
#include <unordered_map>
#include <unordered_set>
#include <cassert>
#include <fstream>
#include <array>
#include <string>
#include <cstring>
#include <functional>
#include <ctime>
#include <iostream>
#include <unordered_set>
#include <complex>

#include <nmmintrin.h>
#include <mmintrin.h>
#include <emmintrin.h>


using namespace std;

#define dprint(Exp,...) if(Exp){fprintf(stderr, __VA_ARGS__);}
#define printe(...) fprintf(stderr, __VA_ARGS__);
//#define printe(...) void();
#define printE(...) fprintf(stderr, __VA_ARGS__);
//#define printE(...) void();


#define PrtExp(_Exp)  cerr<< #_Exp <<" = "<< (_Exp)
#define PrtExpN(_Exp)  cerr<< #_Exp <<" = "<< (_Exp) <<"\n"

#define SINT(n) scanf("%d",&n)
#define SINT2(n,m) scanf("%d %d",&n,&m)
#define SINT3(n,m,o) scanf("%d %d %d",&n,&m,&o)
#define SINT4(n,m,o,P) scanf("%d %d %d %d",&n,&m,&o,&P)
#define SINT5(n,m,o,P,q) scanf("%d %d %d %d %d",&n,&m,&o,&P,&q)
#define SLL(n) scanf("%lld",&n)
#define SLL2(n,m) scanf("%lld %lld",&n,&m)
#define SLL3(n,m,o) scanf("%lld %lld %lld",&n,&m,&o)
#define SST(s) scanf("%s",s)
#define SCH(c) scanf("%c",&c)

#define GC() getchar()

#define PINT(n) printf("%d",(int)(n))
#define PINT2(n,m) printf("%d %d",(int)(n),(int)(m))
#define PINT3(n,m,l) printf("%d %d %d",(int)(n),(int)(m),(int)(l))
#define PLL(n) printf("%lld",(long long)(n))
#define PST(s) printf("%s",(s))
#define PCH(s) printf("%c",(s))

#define PINTN(n) printf("%d\n",(int)(n))
#define PINT2N(n,m) printf("%d %d\n",(int)(n),(int)(m))
#define PINT3N(n,m,l) printf("%d %d %d\n",(int)(n),(int)(m),(int)(l))
#define PLLN(n) printf("%lld\n",(long long)(n))
#define PSTN(s) printf("%s\n",(s))
#define PCHN(s) printf("%c\n",(s))

#define PSP() printf(" ")
#define PN() printf("\n")

#define PC(c) putchar(c)
#define CSP (' ')
#define SN ("\n")

#define rep(i,a) for(int i=0;i<a;i++)
#define reP(i,a) for(int i=0;i<=a;i++)
#define Rep(i,a) for(int i=a-1;i>=0;i--)
#define ReP(i,a) for(int i=a;i>=0;i--)

#define rEp(i,a) for(i=0;i<a;i++)
#define rEP(i,a) for(i=0;i<=a;i++)
#define REp(i,a) for(i=a-1;i>=0;i--)
#define REP(i,a) for(i=a;i>=0;i--)

#define repft(i,a,b) for(int i=a;i<b;i++)
#define repfT(i,a,b) for(int i=a;i<=b;i++)
#define Repft(i,a,b) for(int i=a-1;i>=b;i--)
#define RepfT(i,a,b) for(int i=a;i>=b;i--)

#define foreach(a,it) for(auto it = a.begin(); it != a.end(); ++it)

#define FILL(a,v) fill(begin(a),end(a), v)
#define FILL0(a) memset(a,0,sizeof(a))
#define FILL1(a) memset(a,-1,sizeof(a))

typedef long long ll;

typedef unsigned long long ull;
typedef pair<int, int> Pi;
typedef pair<ll, ll>   Pll;


const int INF = 1'010'000'000; // 0x3C33'6080
const ll INFLL = 0x1f1f1f1f1f1f1f1fLL;//2,242,545,357,980,376,863


template <class A, class B> inline ostream& operator<<(ostream& st, const pair<A, B>& P) { return st << "(" << P.first << "," << P.second << ")"; };
template <class A, class B> inline pair<A, B> operator+(const pair<A, B>& P, const pair<A, B>& Q) { return pair<A, B>(P.first + Q.first, P.second + Q.second); };
template <class A, class B> inline pair<A, B> operator-(const pair<A, B>& P, const pair<A, B>& Q) { return pair<A, B>(P.first - Q.first, P.second - Q.second); };


inline ll gcd(ll a, ll b) { return b ? gcd(b, a % b) : a; }

int bitcount(long bits) {
    bits = (bits & 0x55555555) + (bits >> 1 & 0x55555555);
    bits = (bits & 0x33333333) + (bits >> 2 & 0x33333333);
    bits = (bits & 0x0f0f0f0f) + (bits >> 4 & 0x0f0f0f0f);
    bits = (bits & 0x00ff00ff) + (bits >> 8 & 0x00ff00ff);
    return (bits & 0x0000ffff) + (bits >> 16 & 0x0000ffff);
}

template <class T>
struct fenwick_tree {
    int n;
    std::vector<T> x;
    fenwick_tree(int n_ = 0) : n(n_), x(n + 1, 0) {}
    int size() const { return n; }
    T sum(int r) const {
        T S = 0;
        for (r = r - 1; r >= 0; r = (r & (r + 1)) - 1) S += x[r];
        return S;
    }
    T sum(int l, int r) const { return sum(r) - sum(l); }
    void add(int k, const T& a) {
        for (; k < n; k |= k + 1) x[k] += a;
    }
    void set(int k, const T& a) { add(k, a - sum(k, k + 1)); }
    void clear() {
        x.clear();
        x.resize(n + 1, 0);
    }
};




int main() {

    int l, r, d;
    cin >> l >> r >> d;

    int ret = 0;
    repfT(i, l, r) {
        if (i % d == 0) ++ret;
    }
    cout << ret << endl;



    return 0;
}



Measured memory_bytes: 3632