5
5x5=x
x=25
6x5=x
x=30
5x7=x
x=35
8x5=x
x=40
5x9=x
x=45
6x5=y
y=30
6x6=y
y=36
6x7=y
y=42
8x6=y
y=48
6x9=y
y=54
7x5=z
z=35
6x7=z
z=42
7x7=z
z=49
8x7=z
z=56
7x9=z
8x5=n
n=40
6x8=n
n=48
8x7=n
n=56
8x8=n
n=64
8x9=n
n=72
9x5=q
q=45
6x9=q
q=54
9x7=q
q=63
8x9=q
q=72
9x9=q
q=81