// tested by Hightail - https://github.com/dj3500/hightail
import std.stdio, std.string, std.conv, std.algorithm;
import std.range, std.array, std.math, std.typecons, std.container, core.bitop;

void main() {
    int x, a, b;
    scan(x, a, b);

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


void scan(T...)(ref T args) {
    string[] line = readln.split;
    foreach (ref arg; args) {
        arg = line.front.to!(typeof(arg));
        line.popFront();
    }
    assert(line.empty);
}