#include<bits/stdc++.h>
#define inf 1e9
#define eps 1e-10
#define FOR(i,a,b) for(int i=a;i<=b;i++)
#define REP(i,a,b) for(int i=a;i>=b;i--)
#define db double
#define ve vector<int>
#define pa pair<int,int>
#define fr first
#define sd second
#define pb push_back
#define mp make_pair
#define MEM(a) memset(a,0,sizeof(a))
typedef long long ll;
typedef unsigned long long ull;
using namespace std;
inline ll read()
{
	char ch = getchar();
	ll s = 0, w = 1;
	while (ch < '0' || ch > '9') {if (ch == '-')w = -1; ch = getchar();}
	while (ch >= '0' && ch <= '9') {s = s * 10 + ch - '0'; ch = getchar();}
	return s * w;
}
#define int ll
#define N 110
int n;
ll a[N], p10[20];
string s[N];
void sol()
{
	cin >> n;
	for (int i = 1; i <= n; i ++)cin >> s[i];
	int len = s[1].length() - 2;
	for (int i = 1; i <= n; i ++)
	{
		a[i] = s[i][0] - '0';
		for (int j = 2; j <= s[i].length() - 1; j ++)
		{
			a[i] = a[i] * 10 + s[i][j] - '0';
		}
		a[i] = a[i] * 10;
	}
	for (int K = 1;; K ++)
	{
		int flag = 1;
		for (int i = 1; i <= n; i ++)
		{
			int l = (a[i] - 5) * K, r = (a[i] + 5) * K - 1;
			if ((l + p10[len + 1] - 1) / p10[len + 1] > (r / p10[len + 1])) {flag = 0; break;}
		}
		// if (flag)return ;
		if (flag) {cout << K << '\n'; return ;}
	}
}
signed main()
{
	//freopen(".in","r",stdin);
	//freopen(".out","w",stdout);
	ios::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	p10[0] = 1;
	for (int i = 1; i <= 18; i ++)p10[i] = 10LL * p10[i - 1];
	int T = 1;
	while (T --)sol();
	return 0;
}