#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); i++)
using namespace std;
using ll = long long;
using ld = long double;

int main(){
    cin.tie(0);
    ios::sync_with_stdio(0);

    int A,B; cin >> A >> B;
    auto f = [&](int x) {
        if(0 <= x && x <= min(A, B)) return abs(A + B - 4 * x);
        return int(1e9);
    };
    int ans = 1e9;
    ans = min(ans, f(min(A, B)));
    ans = min(ans, f((A + B) / 4));
    ans = min(ans, f((A + B + 4 - 1) / 4));
    cout << ans << endl;
}