#include <iostream>
#include <fstream>

using namespace std;

int main()
{
	
ifstream infile("sp.inp");
ofstream outfile("sp.out");

long long m,n,t;

infile>>m; 
infile>>n; 
infile>>t;

outfile<<((int)(n/(m+1)))*m*t + ((int)(n%(m+1)))*t;

infile.close();
outfile.close();

return 0; 
}