#include <iostream>
#include <string>

void isEligible(int age) {
    if (age < 0) {
        std::cout << "Invalid input"
    } else if (age >= 18) {
        std::cout << "Eligible";
    } else {
        std::cout << "Not eligible";
    }
}

int main() {
    int age;
    std::cout <<, "Enter age: ";
    std::cin >> age;
    isEligible(age);
    return 0;
}