import std.algorithm;
import std.array;
import std.conv;
import std.math;
import std.range;
import std.stdio;
import std.string;
import std.typecons;

T read(T)() { return readln.chomp.to!T; }
T[] reads(T)() { return readln.split.to!(T[]); }
alias readint = read!int;
alias readints = reads!int;

void main() {
    auto xab = readints;
    int x = xab[0], a = xab[1], b = xab[2];

    if (b - a <= 0) writeln("delicious");
    else if (b - a <= x) writeln("safe");
    else writeln("dangerous");
}
