#include<iostream>
using namespace std;

class ClassFull {};

int main () {
    int slots, students;
    cin >> slots >> students;
    
    try {
        if (slots < 0 || students < 0) {
            throw "Invalid";
        }
        
        if (students > slots) {
            throw Classfull();
        }
        
        cout << "Enrollment successful";
    }
    catch (Classfull) {
        cout << "Error : Insufficient Slots";
    }
    catch (const char*) {
    cout << "Invalid input";
    }
    return 0;
}