//物理数学题#include<stdio.h>#include<string.h>#include<algorithm>using namespace std;int main(){    double h,l,v,ans;    while(scanf("%lf%lf%lf",&h,&l,&v)!=EOF)    {        if(h==0&&l==0&&v==0)break;        ans = h + v * v / 19.6 - 4.9 * l * l / v / v;        printf("%.2lf\n",ans);    }    return 0;}