“Dou itashimashite” (どう致しまして) means “You're welcome” and is widely known as the common response to “arigato gozaimasu”, but it sounds rather stiff and formal. “Iie iie” (いいえいいえ) or “ii yo ii yo” (いいよいいよ) translate as “Not at all” and are casual replies that are more frequently used in daily life.