The combined age of father, mother, and Xiao Ming is 72 years old this year, and the combined age of the three people 5 years ago was 58 years old. How old is Xiao Ming?
爸爸、妈妈、小明三人今年年龄和是72岁，5年前三人的年龄和是58岁．小明今年多少岁．
<result>4</result>