#include <iostream>
#include <iomanip>
#include <vector>
#include <list>
#include <deque>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <algorithm>
#include <cmath>
#include <cstring>
#include <limits>

using namespace std;

#define REP(x,y) for(int x = 0;x < (y);x++)
#define LLI long long int
#define FORR(x,arr) for(auto& x:arr)
#define ALL(a) (a.begin()),(a.end())

#define _L(x) cout<<(x)<<endl

int main()
{
    LLI A, B;
    cin >> A >> B;

    LLI sum = 0;
    if(A > B)
    {
        LLI value =(A - B - 1L);
        sum +=  value > 0 ? value : 0;
        sum += 2000000000 - A;
        cout << sum << endl;
        return 0;
    }
    else
    {
        LLI value =(B - A - 1L);
        sum +=  value > 0 ? value : 0;
        sum += A - 1;
        cout << sum << endl;
        return 0;
    }
}