#include <stdio.h>
#include <atcoder/all>
#include <bits/stdc++.h>
using namespace std;
using namespace atcoder;
using mint = modint998244353;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf32 1000000005
#define Inf64 4000000000000000001LL

int main(){
	
	unsigned long long n;
	long long b;
	cin>>n>>b;
	
	long long nn = n % b;
	for(long long i=0;i<=b+5;i++){
		if((nn*i)%b == 1%b){
			cout<<i<<endl;
			return 0;
		}
	}
	cout<<"NaN"<<endl;
	
	return 0;
}