#include<bits/stdc++.h>
using namespace std;
#define int long long
const int N=2e6+6,mod=1e9+7,INF=2e9;
typedef unsigned long long ull;
typedef long long ll;
typedef pair<int,int> pii;
typedef pair<double,double> pdd;
#define qmi(a,b) a=min(a,b)
#define qma(a,b) a=max(a,b)
#define rep(i,l,r) for(int i=(l);i<=(r);i++)
#define atrep(i,l,r) for(int i=(r);i>=(l);i--)
#define vec vector<int>
#define pb push_back
namespace fast_IO {
#define IOSIZE 100000
	char ibuf[IOSIZE], obuf[IOSIZE], *p1 = ibuf, *p2 = ibuf, *p3 = obuf;
#define getchar() ((p1==p2)and(p2=(p1=ibuf)+fread(ibuf,1,IOSIZE,stdin),p1==p2)?(EOF):(*p1++))
#define putchar(x) ((p3==obuf+IOSIZE)&&(fwrite(obuf,p3-obuf,1,stdout),p3=obuf),*p3++=x)
#define isdigit(ch) (ch>47&&ch<58)
#define isspace(ch) (ch<33)
	template<typename T> inline T read() { T s = 0; int w = 1; char ch; while (ch = getchar(), !isdigit(ch) and (ch != EOF)) if (ch == '-') w = -1; if (ch == EOF) return false; while (isdigit(ch)) s = s * 10 + ch - 48, ch = getchar(); return s * w; }
	template<typename T> inline bool read(T &s) { s = 0; int w = 1; char ch; while (ch = getchar(), !isdigit(ch) and (ch != EOF)) if (ch == '-') w = -1; if (ch == EOF) return false; while (isdigit(ch)) s = s * 10 + ch - 48, ch = getchar(); return s *= w, true; }
	template<typename T> inline void print(T x) { if (x < 0) putchar('-'), x = -x; if (x > 9) print(x / 10); putchar(x % 10 + 48); }
	inline bool read(char &s) { while (s = getchar(), isspace(s)); return true; }
	inline bool read(char *s) { char ch; while (ch = getchar(), isspace(ch)); if (ch == EOF) return false; while (!isspace(ch)) *s++ = ch, ch = getchar(); *s = '\000'; return true; }
	inline void print(char x) { putchar(x); }
	inline void print(char *x) { while (*x) putchar(*x++); }
	inline void print(const char *x) { for (int i = 0; x[i]; i++) putchar(x[i]); }
	inline bool read(std::string& s) { s = ""; char ch; while (ch = getchar(), isspace(ch)); if (ch == EOF) return false; while (!isspace(ch)) s += ch, ch = getchar(); return true; }
	inline void print(std::string x) { for (int i = 0, n = x.size(); i < n; i++) putchar(x[i]); }
	inline bool read(bool &b) { char ch; while(ch=getchar(), isspace(ch)); b=ch^48; return true; }
	inline void print(bool b) { putchar(b+48); }
	template<typename T, typename... T1> inline int read(T& a, T1&... other) { return read(a) + read(other...); }
	template<typename T, typename... T1> inline void print(T a, T1... other) { print(a), print(other...); }
	struct Fast_IO { ~Fast_IO() { fwrite(obuf, p3 - obuf, 1, stdout); } } io;
	template<typename T> Fast_IO& operator >> (Fast_IO &io, T &b) { return read(b), io; }
	template<typename T> Fast_IO& operator << (Fast_IO &io, T b) { return print(b), io; }
#define cout io
#define cin io
#define endl '\n'
} using namespace fast_IO;
const int XR=1e6;
int pr[N],tot,mu[N],pk[N],len=0;
bitset<N>vis;
void Euler(int n,int k){
    mu[1]=1;
    rep(i,2,n){
        if(!vis[i]) pr[++tot]=i,mu[i]=-1;
        for(int j=1;j<=tot&&pr[j]*i<=n;j++){
            vis[i*pr[j]]=1;
            if(i%pr[j]==0){
                mu[i*pr[j]]=0;
                break;
            }else{
                mu[i*pr[j]]=-mu[i];
            }
        }
    }
    rep(i,1,n)  mu[i]+=mu[i-1];
    for(int i=1;i<=tot&&pr[i]<=k;i++){
        while(k%(pr[i]*pr[i])==0)   k/=pr[i];
        if(k%pr[i]==0)pk[++len]=pr[i];
    }
}
unordered_map<int,int>mp1;
int solve1(int x){
    if(x<=XR)   return mu[x];
    if(mp1[x])  return mp1[x];
    int res=1;
    for(int l=2,r=0;l<=x;l=r+1){
        r=(x/(x/l));
        res=res-solve1(x/l)*(r-l+1);
    }
    return res=mp1[x];
}
unordered_map<int,unordered_map<int,int> >F,G;
int f(int n,int k,int now){
    if(!n)  return 0;
    if(k==1)    return n;
    if(F[n][k]) return F[n][k];
    return F[n][k]=f(n,k/pk[now],now+1)-f(n/pk[now],k/pk[now],now+1);
}
int g(int n,int k,int now){
    if(!n)  return 0;
    if(k==1)    return solve1(n);
    if(G[n][k]) return G[n][k];
    return G[n][k]=g(n,k/pk[now],now+1)+g(n/pk[now],k,now);
}
signed main(){
    int n,m,k;
    cin>>n>>m>>k;
    Euler(XR,k);
    int res=0;
    for(int l=1,r=0;l<=min(n,m);l=r+1){
        r=min(n/(n/l),m/(m/l));
        res=res+(f(m/l,k,1))*(g(r,k,1)-g(l-1,k,1))*(n/l);
    }
    cout<<res<<endl;
}