include

using namespace std;

int main() {

int n;
cin >> n;

if (n == 0)
{
    cout << 0 << endl;
    return 0;
}

int sign = 1;
if (n < 0)
{
    sign = -1;
    n = -n;
}

int res = 1;
while (n > 0)
{
    res *= n % 10;
    n /= 10;
}

cout << res * sign << endl;
return 0;

}