#include <iostream>
#include <cstdio>
#include <vector>
#include <algorithm>
#include <cstdlib>
#include <stack>
#include <cstring>
#include <string>
#include <queue>
#include <set>
#define maxn 300000 + 10
#define INF 0x3f3f3f3f
using namespace std;
typedef long long ll;
 
int solve(int n){
    int cnt = 0,sum = 1;
    for(int i = 2; i <= n; i++) {
        if(i % 5 == 0) {
            int temp = i;
            while(temp % 5 == 0) {
                temp /= 5;
                if(temp % 2 == 0)
                    temp /= 2;
                else    cnt ++;
            }
            sum = (sum * temp) % 10;
        } else {
            int temp = i;
            while(cnt > 0 && temp % 2 == 0) {
                temp /= 2;
                cnt --;
            }
            sum = (sum * temp) % 10;
        }
 
    }
    while(cnt > 0){
            cnt--;
            sum/=2...