#include <iostream>

using namespace std;

typedef unsigned long long ull;
ull q(ull a, ull b, ull p)
{
    ull res = 0 ;
    while(b)
    {
        if (b & 1) res = (res + a) %p;
        a = a * 2 % p; 
        b >>= 1; 
    }
    return res;
}

int main()
{
    ull a, b, p;
    cin >> a >> b >> p;
    cout << q(a, b, p) << endl;
    return 0; 
}