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#include <iostream>
using namespace std;

int main()
{
    int n;
    long m, x;
    cin >> n >> m;
    if(n == 1)
    {
        cout << 0;
    }
    else if(n == 2 || m == 1)
    {
        cout << m;
    }
    else if(m == 2)
    {
        x = 1;
        x = x << n;
        x = x - (2 * n - 2);
        cout << x;
    }
    return 0;
}