#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i,n) for (int i=0;i<(int)(n);i++)

int main(){
  int t,s,d;
  cin>>t>>s>>d;
  double tm=double(d)/s;
  double ans=0;
  t+=24-6;
  t%=24;
  if(t>12){
    ans-=t-12;
  }
  tm+=t;
  while(tm>24){
    ans+=12;
    tm-=24;
  }
  if(tm>12){
    ans+=tm-12;
  }
  cout<<fixed<<setprecision(10);
  cout<<ans<<endl;
}