In terms of mixed drinks, shrub is the name of two different, but related, acidulated beverages.
 One type of shrub is a fruit liqueur that was popular in 17th and 18th century England, typically made with rum or brandy mixed with sugar and the juice or rinds of citrus fruit.
A salty dog is a cocktail of tequila, or gin, and grapefruit juice, served in a highball glass with a salted rim.
 The salt is the only difference between a salty dog and a greyhound.
 Vodka may be used as a substitute for tequila; nevertheless, it is historically a tequila drink.
A greyhound is a cocktail consisting of grapefruit juice and either gin or vodka mixed and served over ice.
 If the rim of the glass has been salted, the drink is instead called a salty dog.

Question: Which has more gin, Greyhound or Shrub?
Answer: greyhound