牛爸牛妈帮忙解道数学题

Puzzle is 15 row and 15 line, total 225 cells. Every cell was blank or held a letter for both horizontal word  and a vertical word. Horizontally, there we 10 three letter words, 8 four-letter words, 8 five letter words, 6 six letter words, and some numbers of nine letters-words. Vertically, there were 4 three letter words, 6 four letter words, 6 five letter words, and 10 six letter words, 2 seven letter words, 4 eight letter words and some number of ten letter words. How many cells were blank.