I made it the mantra of those days; when I paused before yet another series of switchbacks or skidded down knee-jarring slopes, when patches of flesh peeled off my feet along with my socks, when I lay alone and lonely in my tent at night I asked, often out loud: Who is tougher than me? The answer was always the same, and even when I knew absolutely there was no way on this earth that it was true, I said it anyway: No one.