Problem:
Score : 100 points

Problem Statement

Takahashi has a strong stomach. He never gets a stomachache from eating something whose "best-by" date is at most X days earlier.
He gets a stomachache if the "best-by" date of the food is X+1 or more days earlier, though.

Other than that, he finds the food delicious if he eats it not later than the "best-by" date. Otherwise, he does not find it delicious.

Takahashi bought some food A days before the "best-by" date, and ate it B days after he bought it.

Write a program that outputs delicious if he found it delicious, safe if he did not found it delicious but did not get a stomachache either, and dangerous if he got a stomachache.

Constraints

1 ≤ X,A,B ≤ 10^9

Input

Input is given from Standard Input in the following format:

X A B

Output

Print delicious if Takahashi found the food delicious; print safe if he neither found it delicious nor got a stomachache; print dangerous if he got a stomachache.

Sample Input 1

4 3 6

Sample Output 1

safe

He ate the food three days after the "best-by" date. It was not delicious or harmful for him.

Sample Input 2

6 5 1

Sample Output 2

delicious

He ate the food by the "best-by" date. It was delicious for him.

Sample Input 3

3 7 12

Sample Output 3

dangerous

He ate the food five days after the "best-by" date. It was harmful for him.

Solution in Rust (1.15.1) (judge verdict: Accepted)

#[cfg(test)]
#[macro_use]
extern crate contest;

use std::fmt::Debug;
use std::io::{self, Bytes, Read, Stdin, StdinLock};
use std::str::{self, FromStr};

fn main() {
    let stdin = io::stdin();
    let mut sc = StdinScanner::new(&stdin);
    let (x, a, b) = (sc.next::<u64>(), sc.next::<u64>(), sc.next::<u64>());
    if a >= b {
        println!("delicious");
    } else if b - a <= x {
        println!("safe");
    } else {
        println!("dangerous");
    }
}


struct StdinScanner<'a> {
    buf: Vec<u8>,
    bytes: Bytes<StdinLock<'a>>,
}


#[allow(dead_code)]
impl<'a> StdinScanner<'a> {
    fn new(stdin: &'a Stdin) -> Self {
        StdinScanner {
            buf: Vec::with_capacity(256),
            bytes: stdin.lock().bytes(),
        }
    }

    fn next<T: FromStr>(&mut self) -> T
        where <T as FromStr>::Err: Debug
    {
        self.buf.clear();
        let mut c = self.bytes.next().unwrap().unwrap();
        while c == ' ' as u8 || c == '\n' as u8 {
            c = self.bytes.next().unwrap().unwrap();
        }
        while !(c == ' ' as u8 || c == '\n' as u8) {
            self.buf.push(c);
            c = self.bytes.next().unwrap().unwrap();
        }
        str::from_utf8(&self.buf).unwrap().parse().unwrap()
    }

    fn vec<T: FromStr>(&mut self, n: usize) -> Vec<T>
        where <T as FromStr>::Err: Debug
    {
        (0..n).map(|_| self.next()).collect()
    }

    fn pairs<A: FromStr, B: FromStr>(&mut self, n: usize) -> Vec<(A, B)>
        where <A as FromStr>::Err: Debug,
              <B as FromStr>::Err: Debug
    {
        (0..n).map(|_| (self.next(), self.next())).collect()
    }

    fn trios<A: FromStr, B: FromStr, C: FromStr>(&mut self, n: usize) -> Vec<(A, B, C)>
        where <A as FromStr>::Err: Debug,
              <B as FromStr>::Err: Debug,
              <C as FromStr>::Err: Debug
    {
        (0..n)
            .map(|_| (self.next(), self.next(), self.next()))
            .collect()
    }

    fn mat<T: FromStr>(&mut self, m: usize, n: usize) -> Vec<Vec<T>>
        where <T as FromStr>::Err: Debug
    {
        (0..n).map(|_| self.vec(m)).collect()
    }
}


trait PrintYn {
    fn print_yn(self, yes: &str, no: &str);
}

impl PrintYn for bool {
    fn print_yn(self, yes: &str, no: &str) {
        println!("{}", if self { yes } else { no });
    }
}