#include<iostream>
#include<exception>
class ClassFullException:public std::exception{};
int main(){
    int slots,students;
    if(!(std::cin>>slots>>students)) return 0;
    if(slots<0||students<0){
        std::cout<<"Invalid input";
    }else{
        try{
            if(students>slots) throw ClassFullException();
            std::cout<"Enrollment successful";
        }catch(const ClassFullException&e){
            std::cout<<"Error:Insufficient slots";
        }
    }
    return 0;
}