Simple as that

Consider three natural numbers $n_{1} ,n_{2}, n_{3}$ defined as

$- n_{1`}=x_{1}x_{2}x_{3}x_{4}$ ( $4~digit~number$ )

$- n_{2}=y_{1}y_{2}y_{3}$ ( $3~digit~number$ )

$- n_{3}=z_{1}z_{2}$ ( $2~digit~number$ )

where $x_{1}....x_{4},y_{1}...y_{3},z_{1},z_{2}$ are all non zero digits .

Then total number of nine digit numbers formed by picking up the digits used in the numbers $n_{1},n_{2},n_{3}$ if digits are taken only from the right side of either of the numbers $n_{1},n_{2}~and~n_{3}$