#include<bits/stdc++.h>
using namespace std;

typedef long long ll;
const ll maxn=2e4, inf=1e18;

unordered_map<ll,ll> lg;

ll v[1005], id[1005][17], dis[maxn], vis[maxn];
string s[1005];
vector<pair<ll,ll> > g[maxn];

ll lowbit(ll x) {
	return x&(-x);
}

struct node {
	ll x;
	ll v;
	bool operator < (const node&other) const{
		return v>other.v;
	}
};

int main() {
	ios::sync_with_stdio(false);
	cin.tie(0), cout.tie(0);
	ll n,tot=0; cin>>n;
	for(ll i=1;i<=16;i++) lg[1<<i]=i;
	for(ll i=1;i<=n;i++) {
		cin>>s[i];
		for(ll j=0;j<s[i].size();j++) v[i]+=((s[i][j]-'0')<<j);
		for(ll j=0;j<=s[i].size();j++) id[i][j]=++tot;
	}
	for(ll i=1;i<=n;i++) {
		for(ll j=0;j<s[i].size();j++) {
			ll len=s[i].size()-j;
			ll val=(v[i]>>j);
			for(ll k=1;k<=n;k++) {
				if(k==i) continue;
				ll x=min(min(lg[lowbit(val^v[k])==0?(1<<16):lowbit(val^v[k])],len),(ll)s[k].size());
				if(x<len&&x<s[k].size()) continue;
				else if(x<len) g[id[i][j]].push_back({id[i][j+x],x});
				else g[id[i][j]].push_back({id[k][x],x});
			}
		}
	}
	priority_queue<node> q;
	for(ll i=1;i<=tot;i++) dis[i]=inf;
	for(ll i=1;i<=n;i++) dis[id[i][0]]=0, q.push((node){id[i][0],0});
	while(q.size()) {
		ll x=q.top().x; q.pop();
		if(vis[x]) continue;
		vis[x]=1;
		for(auto p:g[x]) {
			ll y=p.first, w=p.second;
			if(dis[y]>dis[x]+w) dis[y]=dis[x]+w, q.push((node){y,dis[y]});
		}
	}
	ll ans=inf;
	for(ll i=1;i<=n;i++) ans=min(ans,dis[id[i][s[i].size()]]);
	if(ans!=inf) cout<<ans<<'\n';
	else cout<<"0\n";
	return 0;
}