function main(data){
    input = data.split(" ");
    x = parseInt(input[0],10);
    a = parseInt(input[1],10);
    b = parseInt(input[2],10);
    if(b - a <= 0){
        console.log("delicious");
    }else if(b - a > 0 && b - a <= x){
        console.log("safe");
    }else{
        console.log("dangerous");
    }
}

main(require("fs").readFileSync("/dev/stdin", "utf8"));