Hiring process8 levels
  1. 1 IQ Test
  2. 2 Additional Online Test (If Required)
  3. 3 Office Interview with Hiring Manager
  4. 4 Unpaid Test Task (Motivation Check)
  5. 5 Paid Test Task and Follow-Up Interview
  6. 6 Iterative Paid Test Tasks
  7. 7 Office Verification
  8. 8 Final Interview with the Founder

Problems > Digital Root

Digital Root

Difficulty: 900 2000 ms 128 MB

math

Repeatedly replace N by the sum of its digits until a single digit remains. Print that digit.

Input: one integer N.

Output: the digital root of N.

Constraints:

  • 0 ≤ N ≤ 1018

Sample Tests

Input 1
9875
Output 1
2
Input 2
7
Output 2
7

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