#P5702. Modular Harmonic Sum

    ID: 18930 Type: Default 1000ms 256MiB

Modular Harmonic Sum

Modular Harmonic Sum

Given two integers (n) and (p), along with the smallest primitive root (g) of (p), compute the following sum modulo (p):

[ S = \sum_{i=1}^{n} \frac{1}{i} ]

In other words, you need to calculate (S \bmod p). Note that if you are not familiar with performing modulo operations on fractions, you may refer to this problem for guidance. It is guaranteed that the result exists modulo (p).

inputFormat

The input consists of a single line containing three integers (n), (p), and (g), separated by spaces. Here, (n) is the number of terms in the sum, (p) is a prime modulus, and (g) is the smallest primitive root modulo (p).

outputFormat

Output a single integer which is the value of (S) modulo (p).

sample

5 7 3
1