i n 1 : a " - w{pX " , b " - w{pY " 
 
 i n 1 : c " - vhpX " , d " - vhpY " 
 
 o u t : i " - " , j " - eMO҉" 
 
 o u t : w " - eMO҉^Ry" 
 
 c a l l   S{
 
 