#include <stdio.h>

int main() {
    int age;
    
    //input the age
    scanf("5d",&age);
    
    //check for invalid input
    if(age<0) {
        printf("invalid input");
    }
    else if (age >=18) {
        printf("eligible");
    }
    else {
        printf("not eligible");
    }
    
    return 0;
}