#include <bits/stdc++.h>
using namespace std;

#define int long long





signed main() {
    
   
    int n, b;
    cin >> n >> b;
    int ans = -1;

    for(int i = 0; i <= min(b, n); i++){
        if((i * n) % b == 1){
            ans = i;
            break;
        }
    }
    if(ans == -1){
        cout << "Nan" << endl;
    }
    else{
        cout << ans << endl;
    }


    
    






    
    return 0;
}