#include <iostream>
using namespace std;
int main() {
long long a, b;
cin >> a >> b;
if (a <= 1 && a >= 1000000000){
return 0;}
if (b <= 1 && b >= 1000000000){
return 0;}
if (a * b % 11 != 0){
return 0;}
cout << a * b / 11 << endl;
}
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