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

using ll=long long;
pair<ll,ll> extgcd(ll a,ll b){
  if (b==0) return {1,0};
  auto [y,x]=extgcd(b,a%b);
  y-=a/b*x;
  return {x,y};
}

int main(){
  int n,b;
  cin>>n>>b;
  if (b==1) cout<<0<<endl;
  else if ((n-1)%2==0) cout<<(n-1)/2%b<<endl;
  else{
    if (b%2==0) cout<<"NaN\n";
    else cout<<(n-1)*(extgcd(2,b).first%b+b)%b<<endl;
  }
}