a,b,c,d=input().split()
a,b,c,d=int(a),int(b),int(c),int(d)
if a>b and b>c and c>d:
    print("Fish Diving")
else :
    if a<b and b<c and c<d:
        print("Fish Rising")
    else:
        if a==b and b==c and c==d:
            print("Fish At Constant Depth")
        else :
            print("No Fish")