#include <iostream>
#include <sstream>
#include <cstdio>
#include <vector>
#include <algorithm>
using namespace std;

int main(void){
	int x,a,b;
	cin >> x >> a >> b;
	if(a-b>=0){
		cout << "delicious" << endl;
	}else if(b-a<=x){
		cout << "safe" << endl;
	}else{
		cout << "dangerous" <<endl;
	}
	return 0;
}