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 > Geometric Sum, Large

Geometric Sum, Large

Difficulty: 1800 4000 ms 128 MB

math

Compute A + A·R + A·R² + … + A·RN−1 modulo 109+7.

Input: one line with three integers A, R, N.

Output: the sum mod 109+7.

Constraints:

  • 1 ≤ A, R ≤ 1018
  • 1 ≤ N ≤ 1018

Sample Tests

Input 1
1 2 4
Output 1
15
Input 2
3 1 5
Output 2
15

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