USING: formatting io kernel locals math math.functions math.parser ;
IN: math
MATH: mod ( x y -- z ) foldable flushable
 
IN: template
 
: sum-it ( n -- answer )
   dup 0 =                      ! if
   [ ]                          ! zero in stack
   [   1 -                      ! decrease count by one
       readln string>number     ! read next a_i
       swap                     ! a_i (n - 1) in stack
       sum-it +                 ! recur
   ]
   if ;
 
readln string>number
2
mod
number>string print

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

NQ==

5