SGU 456

#include <iostream>
#include <iomanip>
using namespace std;

double pay(double x,double month,double percent,double total)
{
    double paid=0;
    for(int i=0;i<month;++i)
    {
        double ai=(percent/100)*(total-paid);
        double bi=x-ai;
        paid+=bi;
    }
    return paid;
}

int main()
{
    double s,m,p;
    cin>>s>>m>>p;
    double up=100*s;
    double down=0;
    while(up-down>1e-7)
    {
        double mid=(up+down)/2;
        double total_p=pay(mid,m,p,s);
        if(total_p>s)
            up=mid;
        else
            down=mid;
    }
    cout<<fixed<<setprecision(6)<<(up+down)/2<<endl;
    return 0;
}