8. In the three phrases “尽心尽力” (exert oneself to the utmost), “力可拔山” (strength to move mountains), and “山穷水尽” (at the end of one's resources), each Chinese character represents a number between 1 and 8, with the same character representing the same number and different characters representing different numbers. If the sum of the numbers represented by the characters in each phrase is 19, and “尽” > “山” > “力”, then the maximum value of “水” is $\qquad$