#include <algorithm>
#include <iostream>
#include <sstream>
#include <queue>
#include <deque>
#include <stack>
#include <map>
#include <vector>
#include <string>
#include <set>
#include <cstdio>
#include <cmath>
#include <ctime>
#include <cstdlib>
#include <cstring>

#define sz(a) (int)a.size()
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define llong long long
#define zero(a) fabs(a) < 1e-9
#define resz(a, n) a.clear(), a.resize(n)
#define same(a, n) memset(a, n, sizeof(a))
#define make(a, b) make_pair(a, b)

using namespace std;

const int BOUND = 100000;

llong a, b, c;
set< llong > s;

int main() {
    cin >> a >> b >> c;
    for (int i = 0; i < 20; i++) {
        llong cur = 1;
        for (int j = 0; j <= 2000000; j++) {
            if (s.find(cur) != s.end()) {
                printf("%d\n", j);
                return 0;
            }
            if (j >= i * BOUND && j < (i + 1) * BOUND)
                s.insert(cur);
            cur = (a * cur + (cur % b)) % c;
        }
        s.clear();
    }
    printf("-1\n");
    return 0;
}