RT

#include<bits/stdc++.h>
using namespace std;
double mc,mg,t,cE,g,v,h;
signed main(){
    cin>>mc>>mg>>t>>cE>>g;
    double mt=mc-mg,dm=mt/t;
    double T=dm*cE;
    for(double i=0;i<t;i+=0.01){
        double a=T/(mt+mg)-g;
        double dv=a*0.01;v+=dv;
        double dh=v*0.01;h+=dh;
        mt-=dm*0.01;
    }
    printf("%.3lf\n",h);
    return 0;
}