D$.$ Divisible Pairs

time limit per test: $2$ seconds memory limit per test: $256$ megabytes

Polycarp has two favorite integers $x$ and $y($they can be equal$),$ and he has found an array $a$ of length $n.$

Polycarp considers a pair of indices $a_i+a_{j}x{a}_i-a_{j}yx=5,y=2,n=6,a=[1,2,7,4,9,6]($:$1,5$:$)$:$a_1+a_5=1+9=10$