#include<bits/stdc++.h>
using namespace std;
int main(){
    long a,b;
    cin >> a >> b;
    map<long,bool>m;
    int ans = 1;
    long n = b;
    while(n != 0){
        if(m[n]){
            ans = -1;
            break;
        }else{
            m[n] = true;
        }
        n = a*n + b;
        ans++;
    }
    cout << ans << endl;
    
}