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Problems > Geometric Series Modulo

Geometric Series Modulo

Difficulty: 1600 2000 ms 128 MB

math

Compute A + Aq + Aq2 + … + AqN−1 modulo 109+7.

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

Output: the series sum mod 109+7.

Constraints:

  • 1 ≤ A, q ≤ 109
  • 1 ≤ N ≤ 1018

Sample Tests

Input 1
1 2 10
Output 1
1023
Input 2
5 1 3
Output 2
15

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