#include <bits/stdc++.h>
using namespace std;
#include <atcoder/all>
using namespace atcoder;
using ll = long long;
int N,B;

void solve(){
    for(int i = 0;i<B;i++){
        if((N%B)*(i)%B==1%B){
            cout<<i<<endl;
            return;
        }
    }
    cout<<"NaN"<<endl;
}

signed main(){
    cin >> N >> B;
    solve();
}