In this task, you will use your knowledge about language (and common sense) to determine what element the marked number refers to. The numbers are marked with two underlines around them, like: _ number _. Your answer should be chosen from the given text, and should not contain other words.

Ex Input:
DC Endeavour Morse:  Strange , there 's a blackboard there . Could you ... ? Each element is assigned a symbol : Typically an abbreviation of its name together with a unique one or two - digit atomic number . Can you write these down as I call then off ? So , 74 gives us Tungsten . _ 17 _ , Chlorine . 18 , Argon . 19 , Potassium . The elements spell out a name .
Chief Superintendent Bright: T.C.A.P Tucap ?
DC Endeavour Morse: No , not quite , sir , but you 're on the right lines .
DC Endeavour Morse: Um
DC Endeavour Morse: , the chemical symbol for Tungsten is n't Tu as you might expect . It 's W from the German Wolframite . And Potassium is n't P as you might expect but K after the Latin Kalium . Taken together they 're Tungsten ...
DC Endeavour Morse: ...
DC Endeavour Morse: Chorine ...
DC Endeavour Morse: ...
DC Endeavour Morse: Argon ...
DC Endeavour Morse: ...
DC Endeavour Morse: and Potassium .
DC Endeavour Morse: W
DC Endeavour Morse: - C - L - A - R - K. Wallace Clark .
Chief Superintendent Bright: Good
Chief Superintendent Bright: grief .
DI Fred Thursday: Derek 's father .
Chief Superintendent Bright: But there 's nothing to say he even knew the vicar .
DC Endeavour Morse: Ivy Clark , sir . Wallace 's wife is buried in the churchyard . The next plot but one to Lady Daphne Sloan . Reverend Monkford performed the service .
PC Jim Strange: Bloody hell , matey . That 's ...
DI Fred Thursday: Elementary .

Ex Output:
number


Ex Input:
The Doctor:  Those shields wo n't hold them there for long .
Briggs: They 'll last until we 're back to Earth .
The Doctor: And then ?
Briggs: There 's only a few of them : our security men will cope with them .
The Doctor: They 're an invasion force , Earth is where they want to go . There are considerably more than a few on board .
Adric: How many of these silos are you carrying ?
Briggs: Oh , _ fifteen _ thousand or ...
Briggs: No
Briggs: . It 's not possible !

Ex Output:
silos


Ex Input:
Evelyn Williams:  What about the past ?
Patrick Bateman: We never really shared _ one _ .

Ex Output:

past