#include<bits/extc++.h>
using namespace std;
using ui=unsigned int;
using uli=unsigned long long int;
using li=long long int;
namespace pbds=__gnu_pbds;
static constexpr ui pows[6]={100000,10000,1000,100,10,1};
struct Pswd{
    ui x;
    friend istream& operator>>(istream& in,Pswd& x){
        x.x=0;
        for (signed char i=0;i<5;++i){
            char k;
            in>>k;
            x.x=x.x*10+k-'0';
        }
        return in;
    }
    signed char operator[](unsigned char p){return x%pows[p]/pows[p+1];}
};
bool check(Pswd a,Pswd b){
    signed char p0=-1,p1=-1;
    for (unsigned char i=0;i<5;++i) if (a[i]!=b[i]){
        if (p0==-1) p0=i;
        else if (p1==-1) p1=i;
        else return false;
    }
    if (p1==-1) return true;
    else
        if (p1-p0!=1) return false;
        else return (a[p0]-b[p0]+10)%10==(a[p1]-b[p1]+10)%10;
}
int main(void){
#ifndef DEBUG
    ios::sync_with_stdio(false),cin.tie(nullptr),cout.tie(nullptr);
#endif
    size_t n;
    cin>>n;
    vector<Pswd> status(n);
    for (Pswd& i:status) cin>>i;
    size_t ans=0;
    for (ui i=0;i<=99999;++i){
        Pswd now{i};
        bool flag=true;
        for (Pswd j:status) if (j.x==i||!check(now,j)){flag=false;break;}
        ans+=flag;
    #ifdef DEBUG
        if (flag) cout<<now.x<<'\n';
    #endif
    }
    cout<<ans;
    return 0;
}