Utility function to calculate the sum for x 4 ' s , ▁ y ▁ 5' s and z 6 's
function getSum ( x , y , z ) { let ans = 0 ; exactnum [ 0 ] [ 0 ] [ 0 ] = 1 ; for ( let i = 0 ; i <= x ; ++ i ) { for ( let j = 0 ; j <= y ; ++ j ) { for ( let k = 0 ; k <= z ; ++ k ) {