10680 - LCM

#include<bits/stdc++.h>
using namespace    std;
#define pb                push_back
#define mx                1000006

typedef long long int       ll;

vector<int>prime;
bool vis[mx];
void sieve()
{
      for(int i=3; i*i<=mx; i+=2)
      {
          if(vis[i]==0)
          {
              for(int j = i*i; j<mx; j+=2*i)
              vis[j]=1;
          }
      }

      prime.pb(2);
      for(int i=3; i<mx; i+=2)
        if(vis[i]==0)prime.pb(i);
}




int main()
{

     sieve();

      int n;
      while(cin>>n)
      {
         if(n==0)return 0;
         int arr[n+5]={0};
         for(int i=0; prime[i]<=n; i++)
         {
              int x = prime[i];
            while(1)
            {
              if(x<=n)
              {
                arr[prime[i]]++;
              }
              else break;
              x*=prime[i];
            }
         }

        int ans = 1;
         for(int i=2; i<=n; i++)
         {
            if(arr[i])
            {
              int x = arr[i];
              while(x--)
              {
                ans*=i;
              }
            }
         }

          while(1)
          {
            if(ans%10!=0)
            {
              cout<<ans%10<<endl;
              break;
            }
            ans/=10;
          }
      }
    return 0;
}