#include<stdio.h.>
int main(){
    float bmi;
    scanf("%f", &bmi);
    if(bmi < 0.0 || bmi > 100.0 ){
        printf("Invalid input");
    }
    else if (bmi < 18.5){
        printf("underweight");
    }else if (bmi >= 18.5 && bmi <= 24.9){
        printf("normal weight");
    }else if (bmi >= 25.0){
        printf("overweight");
    }
    return 0;
}