include

include

using namespace std;

int main() {

int n;
int num = 1;
bool single = false;
cin >> n;

if (n == 0) {
	cout << n;
	goto end;
} else if (n < 0) {
	single = true;
	n = abs(n);
}

while (n) {
	num *= n % 10;
	n /= 10;
}

if (single) {
	cout << -num << endl;
} else {
	cout << num << endl;
}

end:

return 0;

}