#include <iostream>
#include <cstring>
using namespace std;
string s[1000005];
int cnt[1000005];
string res;
int main(){
	int n;
	cin>>n;
	int cur=0,total_length=0,dif=0; 
	for(int i=1;i<=n;i++) cin>>s[i],total_length+=s[i].length();
	while(total_length){
		int cur_total=total_length;
		for(int i=1;i<=n;i++)
			while(s[i][cnt[i]]==char(cur+'0') and cnt[i]<s[i].length()){
				res+=s[i][cnt[i]++];
				total_length--;
			}
		cur=1-cur;
		if(cur_total!=total_length)dif++;
	}
	cout<<res.length()-dif<<endl;
}