fun f (x) {
  fun inner1 (y) {
     if y == 0 then 0 else inner2 (y-1) fi
  }
  
  fun inner2 (y) {
     if y == 0 then 0 else inner1 (y-1) fi
  }  

   inner1 (x)
}

local n = read ();

write (f (5))