#include<iostream>
#include<cmath>
#include<vector>
using namespace std;
int main(){
long long a, b, c;
cin>>a>>b>>c;
long long sum=0;
for(long long i=1; i<=a; i++){
    for(long long j=1; j<=b; j++){
        for(long long k=1; k<=c; k++){
            //cout<<1;
            long long d=i*j*k;
            //cout<<d;
            vector<int> is;
            for(long long f=2; f*f<=d; f++){
                while(d%f==0){
                    is.push_back(f);
                    d/=f;
                }
            }
            if(d>1)
                is.push_back(d);
            long long count=1, finish=1;
            //cout<<1;
            for(long long f=0; f<is.size()-1; f++){
                //cout<<1;
                //cout<<is[f]<<" "<<is[f+1];
                if(is[f]==is[f+1]){
                    count++;
                    //cout<<count;
                }
                else{
                    finish*=(count+1);
                }
                //cout<<1;
            }
            cout<<finish<<endl;
            sum+=finish;
        }
    }
}
cout<<sum;
return 0;
}