#define _USE_MATH_DEFINES
#include<stdio.h>
#include<string>
#include<iostream>
#include<cctype>
#include<cstdio>
#include<vector>
#include<stack>
#include<queue>
#include <algorithm>
#include<math.h>
#include<set>
#include<map>
#include<iomanip>

//#include<bits/stdc++.h>



using namespace std;




int main() {

	long long int a,b,ans=0;;
	cin>>a>>b;
	if(a>b){
		ans+=2000000000-a-1;
		ans+=a-b;
	}
	else{
		ans+=b-2;
	}
	cout<<ans<<endl;
	return 0;
}