package main
import("fmt"; "math"; "os")

func main(){
    n:=2000000000
    hn:=0.0
    for k:=n;k>=1;k-- {
        hn+=1.0/float64(k)
    }
    fmt.Printf("gamma(%d) = %.14f\n",n,hn-math.Log(float64(n)));
    os.Exit(0)
}