codeagon-b

//  [amitdu6ey]
// g++ -std=c++11 -o2 -Wall filename.cpp -o filename
#include <bits/stdc++.h>
#define hell 1000000009
#define bug1(x) cout<<":"<<x
#define bug2(x) cout<<":"<<x
#define bug3(x) cout<<"# "<<x<<" #"<<endl
#define ll long long
#define pb push_back
#define mp make_pair
#define tr(z) for(auto it=z.begin(); it!=z.end(); it++)
#define rloop(i,a,b) for(long long i=a; i>=b;i--)
#define loop(i,a,b) for(long long i=a; i<b; i++)
#define vbool vector< bool >
#define vvbool  vector< vector<bool> >
#define vchar vector<char>
#define vi vector<int>
#define vvi vector< vector<int> >
#define pll pair<long long, long long>
#define vll vector<long long>
#define vvl vector< vector<long long> >
#define ninf numeric_limits<long long>::min()
#define pinf numeric_limits<long long>::max()
#define comp(a,b) (abs(a-b)<1e-9) // to compare doubles

using namespace std;

ll n;
string s;
map<char, ll> f;
vchar digs = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9'};
vchar odds;
bool possible_left[10][100009];
bool possible_right[10][100009];


bool contains(ll l, ll r){
    /*this function return true if all elements
    in odds vector occur in this range in ~ O(1).*/
    bool ans=true;
    for(char odd : odds){
        if(!possible_left[(int)(odd-'0')][r] or !possible_right[(int)(odd-'0')][l]){
            return false;
        }
    }
    return true;
}

bool is_found(ll len){
    /* this function return true if any substring of length
    len is posssible which contains all element of odds vector*/
    for(ll i=0;i<n-len;i++){
        bool ans=true;
        ll l=i, r=i+len-1;
        if(contains(l,r)){
            return true;
        }
    }
    return false;
}

void solve(){
    cin>>n;
    cin>>s;
    loop(i,0,10){
        loop(j,0,n+1){
            possible_left[i][j]=false;  //it tells whether number i is present on left of index j
            possible_right[i][j]=false; //it tells whether number i is present on right of index j
        }
    }
    for(int i=0;i<=9;i++){
        for(int j=0;j<n;j++){
            if((int)(s[j]-'0')==i){
                loop(k,j,n) possible_left[i][k]=true;
                break;
            }
        }
        for(int j=n-1;j>=0;j--){
            if((int)(s[j]-'0')==i){
                loop(k,0,j+1) possible_right[i][k]=true;
                break;
            }
        }
    }

    for(ll i=0;i<n;i++){
        f[s[i]]++;  // couinting frequency of every num
    }

    for(auto d : digs){
        if(f[d]%2!=0 and f[d]!=0){
            odds.pb(d); // if odd frequency put it in odds array
        }
    }
    // binary search on length
    ll l=0, r=n;
    ll ans=pinf;
    while(l<=r){
        ll len=(l+r)/2;
        if(is_found(len)){
            r=len-1;
            ans=min(ans, len);
        }
        else{
            l=len+1;
        }
    }
    // corner cases
    if(odds.size()==0)   ans=-1;
    if(odds.size()==1) ans=0;
    cout<<ans<<"\n";
    return;
}

int main(){
    ios_base::sync_with_stdio(0);
    cout.tie(0);
    cin.tie(0);
    //freopen("input.txt","r",stdin);
    //freopen("output.txt","w",stdout);
    int test_cases=1;
    //cin>>test_cases;
    while(test_cases--){
      solve();
    }
    return 0;
}