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

using ll=long long;
ll modpow(ll n,ll k,ll mod){
  ll pw=n;
  ll ret=1;
  while (k){
    if (k%2==1){
      ret*=pw;
      ret%=mod;
    }
    pw=pw*pw;
    pw%=mod;
    k/=2;
  }
  return ret;
}
  
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)*modpow(2,b-2,b)%b<<endl;
  }
}