CodeForces

//可谓是非常水的题了，没什么可说的#include <bits/stdc++.h>using namespace std;int main(){int k, r;while (cin >> k >> r){int i = 1;for (i = 1; ;i++){int tp = i * k % 10;if (tp == 0 || tp == r)break;}cout << i << endl;}return 0;}