#line 2 "cpplib/util/template.hpp"
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#pragma GCC target("avx2")
#include<bits/stdc++.h>
using namespace std;
struct __INIT__{__INIT__(){cin.tie(0);ios::sync_with_stdio(false);cout<<fixed<<setprecision(15);cerr<<fixed<<setprecision(15);}}__INIT__;
typedef long long lint;
#define INF (1LL<<60)
#define IINF (1<<30)
#define EPS (1e-10)
#define endl ('\n')
typedef vector<lint> vec;
typedef vector<vector<lint>> mat;
typedef vector<vector<vector<lint>>> mat3;
typedef vector<string> svec;
typedef vector<vector<string>> smat;
template<typename T>using V=vector<T>;
template<typename T>using VV=V<V<T>>;
template<typename T>inline void output(T t){bool f=0;for(auto i:t){cout<<(f?" ":"")<<i;f=1;}cout<<endl;}
template<typename T>inline void output2(T t){for(auto i:t)output(i);}
template<typename T>inline void debug(const T& t){
    #ifdef DEBUG
    for(auto e=begin(t);e!=end(t);++e)cerr<<*e<<" ";
    cerr<<endl;
    #endif
}
template<typename T>inline void debug2(T t){for(auto i:t)debug(i);}
#define loop(n) for(long long _=0;_<(long long)(n);++_)
#define _overload4(_1,_2,_3,_4,name,...) name
#define __rep(i,a) repi(i,0,a,1)
#define _rep(i,a,b) repi(i,a,b,1)
#define repi(i,a,b,c) for(long long i=(long long)(a);i<(long long)(b);i+=c)
#define rep(...) _overload4(__VA_ARGS__,repi,_rep,__rep)(__VA_ARGS__)
#define _overload3_rev(_1,_2,_3,name,...) name
#define _rep_rev(i,a) repi_rev(i,0,a)
#define repi_rev(i,a,b) for(long long i=(long long)(b)-1;i>=(long long)(a);--i)
#define rrep(...) _overload3_rev(__VA_ARGS__,repi_rev,_rep_rev)(__VA_ARGS__)

// #define rep(i,...) for(auto i:range(__VA_ARGS__)) 
// #define rrep(i,...) for(auto i:reversed(range(__VA_ARGS__)))
// #define repi(i,a,b) for(lint i=lint(a);i<(lint)(b);++i)
// #define rrepi(i,a,b) for(lint i=lint(b)-1;i>=lint(a);--i)
// #define irep(i) for(lint i=0;;++i)
// inline vector<long long> range(long long n){if(n<=0)return vector<long long>();vector<long long>v(n);iota(v.begin(),v.end(),0LL);return v;}
// inline vector<long long> range(long long a,long long b){if(b<=a)return vector<long long>();vector<long long>v(b-a);iota(v.begin(),v.end(),a);return v;}
// inline vector<long long> range(long long a,long long b,long long c){if((b-a+c-1)/c<=0)return vector<long long>();vector<long long>v((b-a+c-1)/c);for(int i=0;i<(int)v.size();++i)v[i]=i?v[i-1]+c:a;return v;}
// template<typename T>inline T reversed(T v){reverse(v.begin(),v.end());return v;}
#define all(n) begin(n),end(n)
template<typename T,typename E>bool chmin(T& s,const E& t){bool res=s>t;s=min<T>(s,t);return res;}
template<typename T,typename E>bool chmax(T& s,const E& t){bool res=s<t;s=max<T>(s,t);return res;}
const string ds="DRUL";
const vector<lint> dx={1,0,-1,0,1,1,-1,-1};
const vector<lint> dy={0,1,0,-1,1,-1,1,-1};
#define SUM(v) accumulate(all(v),0LL)
#if __cplusplus>=201703L
    template<typename T,typename ...Args>auto make_vector(T x,int arg,Args ...args){if constexpr(sizeof...(args)==0)return vector<T>(arg,x);else return vector(arg,make_vector<T>(x,args...));}
#endif
#define extrep(v,...) for(auto v:__MAKE_MAT__({__VA_ARGS__}))
#define bit(n,a) ((n>>a)&1)
vector<vector<long long>> __MAKE_MAT__(vector<long long> v){if(v.empty())return vector<vector<long long>>(1,vector<long long>());long long n=v.back();v.pop_back();vector<vector<long long>> ret;vector<vector<long long>> tmp=__MAKE_MAT__(v);for(auto e:tmp)for(long long i=0;i<n;++i){ret.push_back(e);ret.back().push_back(i);}return ret;}
using graph=vector<vector<int>>;
template<typename T>using graph_w=vector<vector<pair<int,T>>>;
template<typename T,typename E>ostream& operator<<(ostream& out,pair<T,E>v){out<<"("<<v.first<<","<<v.second<<")";return out;}
#if __cplusplus>=201703L
    constexpr inline long long powll(long long a,long long b){long long res=1;while(b--)res*=a;return res;}
#endif

template<typename T,typename E>pair<T,E>& operator+=(pair<T,E>&s,const pair<T,E>&t){s.first+=t.first;s.second+=t.second;return s;}
template<typename T,typename E>pair<T,E>& operator-=(pair<T,E>&s,const pair<T,E>&t){s.first-=t.first;s.second-=t.second;return s;}
template<typename T,typename E>pair<T,E> operator+(const pair<T,E>&s,const pair<T,E>&t){auto res=s;return res+=t;}
template<typename T,typename E>pair<T,E> operator-(const pair<T,E>&s,const pair<T,E>&t){auto res=s;return res-=t;}
// 128*1024*1024
#define BEGIN_STACK_EXTEND(size) void * stack_extend_memory_ = malloc(size);void * stack_extend_origin_memory_;char * stack_extend_dummy_memory_ = (char*)alloca((1+(int)(((long long)stack_extend_memory_)&127))*16);*stack_extend_dummy_memory_ = 0;asm volatile("mov %%rsp, %%rbx\nmov %%rax, %%rsp":"=b"(stack_extend_origin_memory_):"a"((char*)stack_extend_memory_+(size)-1024));
#define END_STACK_EXTEND asm volatile("mov %%rax, %%rsp"::"a"(stack_extend_origin_memory_));free(stack_extend_memory_);
#line 3 "cpplib/math/binary_search.hpp"
/**
 * @brief 二分探索
 */
template<typename T=long long,typename F>
T bs(T mn,T mx,F func){
    mn--;
    mx++;
	while(mx-mn>1){
		T mid=(mn+mx)/2;
		if(!func(mid))mx=mid;
		else mn=mid;
	}
    return mn;
}
#line 2 "cpplib/math/is_prime.hpp"
#include <initializer_list>
/**
 * @brief 素数判定(高速)
 */
bool is_prime(long long n){
    if(n<=1)return 0;
    if(n==2)return 1;
    if(n%2==0)return 0;
    long long s=0,d=n-1;
    while(d%2)d/=2,s++;
    auto mod_pow=[](__int128_t a,__int128_t b,__int128_t n){
        long long res=1;
        while(b){
            if(b%2)res=res*a%n;
            a=a*a%n;
            b/=2;
        }
        return (long long)(res);
    };
    for(long long e:{2,3,5,7,11,13,17,19,23,29,31,37}){
        if(n<=e)break;
        if(mod_pow(e,d,n)==1)continue;
        bool b=1;
        for(int i=0;i<s;i++){
            if(mod_pow(e,d<<i,n)==n-1)b=0;
        }
        if(b)return 0;
    }
    return 1;
}
#line 8 "cpplib/math/prime_factor.hpp"

/**
 * @brief 素因数分解(高速)
 */

void __prime_factor(long long n,long long& c,std::vector<long long>& v){
    if(n==1)return;
    if(n%2==0){
        v.emplace_back(2);
        __prime_factor(n/2,c,v);
        return;
    }
    if(is_prime(n)){
        v.emplace_back(n);
        return;
    }
    while(1){
        long long x=2,y=2,d=1;
        while(d==1){
            x=((__int128_t)x*x+c)%n;
            y=((__int128_t)y*y%n+c)%n;
            y=((__int128_t)y*y%n+c)%n;
            d=std::gcd(std::abs(x-y),n);
        }
        if(d==n){
            c++;
            continue;
        }
        __prime_factor(d,c,v);
        __prime_factor(n/d,c,v);
        return;
    }
}

std::map<long long,long long> prime_factor(long long n){
    std::vector<long long>v;
    long long c=1;
    __prime_factor(n,c,v);
    std::map<long long,long long>m;
    for(auto e:v){
        m[e]++;
    }
    return m;
}
#line 4 "main.cpp"

int main(){
    lint n,k,m;
    cin>>n>>k>>m;
    m=prev(prime_factor(m).end())->first;
    lint res=0;
    {
        lint tmp=n;
        while(tmp){
            tmp/=m;
            res+=tmp;
        }
    }
    {
        lint tmp=k;
        while(tmp){
            tmp/=m;
            res-=tmp;
        }
    }
    {
        lint tmp=n-k;
        while(tmp){
            tmp/=m;
            res-=tmp;
        }
    }
    cout<<res<<endl;
}