#include<bits/stdc++.h>

using namespace std;

const int inf=1e9;

int x,y,n;

double dfs(double x,double y,int n)

{

    if(n==)return max(x,y)/min(x,y);

    double sum=1.0*inf;

    double xx=x/n,yy=y/n;

    for(int i=;i<=(n>>);i++)

    sum=min(sum,max(dfs(xx*i,y,i),dfs(x-xx*i,y,n-i))),

    sum=min(sum,max(dfs(x,yy*i,i),dfs(x,y-yy*i,n-i)));

    return sum;

}

int main()

{

    scanf("%d%d%d",&x,&y,&n);

    printf("%.6lf\n",dfs(1.0*x,1.0*y,n));

}