perfect square
factor and find pairs to make perfect square
example
36=2*2*3*3=(2*2)*(3*3)
we need paris
factor 112
112=2*2*2*2*7=(2*2)*(2*2)*(7)
we need a pair for 7
so we just need to multiply it by 7
112*7=784
784=2*2*2*2*7*7=(2*2)(2*2)(7*7)=28^2
answer is 7