#include <iostream>#include <cstdio>#include <algorithm>#include <map>#include <vector>#include <cstring>#include <cmath>using namespace std;typedef long long ll;const int maxn = 7e4+10;int table[4][4]={6,2,4,8, 1,3,9,7, 1,7,9,3, 1,9,1,9,};int n,m;int getpow(int n,int p){ int q=p,res=0; while(n>=q){res+=n/q;q*=p;} return res;}int g(int n,int x){ if(n==0) return 0; return n/10+(n%10>=x?1:0)+g(n/5,x);}int f(int n,int x){ if(n==0) return 0; return f(n/2,x)+g(n,x);}int solve(){ int ans=1; int pow_2=getpow(n,2)-getpow(n-m,2)-getpow(m,2); int pow_5=getpow(n,5)-getpow(n-m,5)-getpow(m,5); if(pow_2<pow_5) return 5; else if(pow_2==pow_5) ans=1; else ans*=table[0][(pow_2-pow_5)%4]; int pow_3=f(n,3)-f(n-m,3)-f(m,3);pow_3=(pow_3%4+4)%4; int pow_7=f(n,7)-f(n-m,7)-f(m,7); int pow_9=f(n,9)-f(n-m,9)-f(m,9); ans=(ans*table[1][pow_3%4])%10; ans=(ans*table[2][pow_7%4])%10; ans=(ans*table[3][pow_9%4])%10; return ans;}int main(){ while(cin>>n>>m){ cout<<solve()<<endl; } return 0;}
