tle uva10680.cpp

#include <bits/stdc++.h>
using namespace std;
#define test int t; cin>>t; while (t--)
#define ll long long int
#define Faster  ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define pi acos(-1)
#define yes printf("YES\n");
#define no printf("NO\n");
ll a[1000008];
int gcd(int a,int c)
{
    while(c)
    {
        a=a%c;
        swap(a,c);
    }
    return a;
}
ll findLcm(ll x[],ll n)
{
    ll ans=x[0];
    for(ll i=1;i<n;i++)
    {
        ans=(x[i]*ans)/(gcd(x[i],ans));
    }
    return ans;
}

int main()
{
   Faster
   ll n,c,d,e,f,i,j,k,l;
   while(cin>>n && n)
   {
       for(i=0;i<n;i++)
       {
           a[i]=i+1;
       }
       c= findLcm(a,n);
       while(1)
       {
           d=c%10;
           c=c/10;
           if(d)
           {
               cout<<d<<endl;
               break;
           }

       }
   }
   return 0;
}