#include <bits/stdc++.h>

#define     fr              freopen("input.txt","r",stdin)
#define     fw              freopen("output.txt","w",stdout)
#define     fast            ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL)


#define     ll              long long int
#define     ld              long double
#define     ul              unsigned long long int
#define     dl              double
#define     st              string

#define     vb              vector<bool>
#define     vll             vector <ll>
#define     lll             list <ll>
#define     ls              list<string>
#define     lc              list <char>
#define     qll             queue <ll>
#define     stll            stack <ll>
#define     sll             set <ll>
#define     sts             set <string>
#define     vs              vector <string>
#define     pll             pair <ll,ll>
#define     mll             map <ll,ll>
#define     msl             map <string,ll>
#define     vecp            vector < pair <ll, ll> >
#define     vecpp           vector < pair <ll, pair <ll, ll> > >
#define     pb              push_back
#define     pf              push_front
#define     in              insert
#define     eb              emplace_back
#define     ppb             pop_back
#define     ppf             pop_front

#define     el              endl
#define     rt              return 0

#define     N               cout << "NO" << endl
#define     Y               cout << "YES" << endl
#define     pr(a)           cout <<a<< endl

#define     gcd(a, b)       __gcd(a, b)
#define     lcm(a, b)       (a * b) / gcd(a, b)

#define     len(X)          ((ll)X.size())



#define     wh                  while
#define     rep(i, l, r)        for(long long i = l; i<r; i++)
#define     repi(i, l, r, p)    for(long long i = l; i<r; i+=p)
#define     repi2(i, l, r, p)   for(long long i = l; i>=r; i+=p)
#define     repb(i, r, l)       for(long long i = r; i>=l; i--)
#define     repbd(i, r, l, d)   for(long long i = r; i>l; i-=d)
#define     repr(i, begin, end) for (__typeof(end) i = (begin) - ((begin) > (end)); i != (end) - ((begin) > (end)); i += 1 - 2 * ((begin) > (end))) ///traverse a array!!

#define     max3(a, b, c)       max(a, max(b, c))
#define     max4(a, b, c, d)    max(max(a, b), max(c, d))
#define     min3(a, b, c)       min(a, min(b, c))
#define     min4(a, b, c, d)    min(min(a, b), min(c, d))

#define     vsort(v)            sort(v.begin(),v.end())
#define     all(container)      container.begin(), container.end()
#define     iterate(v, it)      for(vector< long long >::const_iterator it = v.begin(); it != v.end(); it++)

#define     rand(V)             random_shuffle(all(V))
#define     lb(a,X)             lower_bound(all(a),X)-a.begin()
#define     ub(a,X)             upper_bound(all(a),X)-a.begin()

#define     BIG                 300000


using namespace std;

const int MOD = 1e9+7; // 998244353;
const int MAX = 2e5+5;
const ll INF = 1e18;
const double PI = acos(-1.0);

int main()
{


    ll a,b,i,c,d,n,t,e,r,f=0,g,h;
//    st w,y,s,z;
//     scanf("%lld",&t);
//    wh(t--)
//    {
     cin>>a>>b>>c;
     while(a<=b)
     {
         if(a%c==0)
            f++;
        a++;
     }
     cout<<f<<endl;



//    }
    rt;
}






Measured memory_bytes: 3620