#include "bits/stdc++.h" using namespace std; typedef long long ll; typedef pair pii; typedef pair pll; const int INF = 1e9; const ll LINF = 1e18; template ostream& operator << (ostream& out,const pair& o){ out << "(" << o.first << "," << o.second << ")"; return out; } template ostream& operator << (ostream& out,const vector V){ for(int i = 0; i < V.size(); i++){ out << V[i]; if(i!=V.size()-1) out << " ";} return out; } template ostream& operator << (ostream& out,const vector > Mat){ for(int i = 0; i < Mat.size(); i++) { if(i != 0) out << endl; out << Mat[i];} return out; } template ostream& operator << (ostream& out,const map mp){ out << "{ "; for(auto it = mp.begin(); it != mp.end(); it++){ out << it->first << ":" << it->second; if(mp.size()-1 != distance(mp.begin(),it)) out << ", "; } out << " }"; return out; } /* 問題文============================================================ ================================================================= 解説============================================================= ================================================================ */ ll solve(){ ll res = 0; string N,M; cin >> N >> M; if(M == "0") return 1; int V = *N.rbegin() - '0'; vector cycle(10); vector cyclev; int cyclelen = 0; while(cycle[V] == 0){ cycle[V] = ++cyclelen; cyclev.push_back(V); V = V*V%10; } int cycleid = 0; for(auto c:M){ cycleid = 10*cycleid + c - '0'; cycleid%=cyclelen; } for(int i = 0; i < 10;i++){ if(cycleid+1 == cycle[i]) res = i; } return res; } int main(void) { cin.tie(0); ios_base::sync_with_stdio(false); cout << solve() << endl; return 0; }