public class EulerNumber {
public static void main(String[] args) {
double e=1.0;
double t=1.0;
for (int i=1;factorial(i)<1e-5;i++) {
t/=i;
e+=t;
}
System.out.println(e);
}
private static long factorial(long factorial){
if(factorial == 1){
return 1;
}
return factorial * factorial(factorial-1);
}
}