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