//Md. Shajibul Islam..
//East West University, CSE Department'19
 
#include<bits/stdc++.h>
using namespace std;
 
typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<vi> vvi;
typedef vector<vl> vvl;
typedef pair<int,int> pii;
typedef pair<double, double> pdd;
typedef pair<ll, ll> pll;
typedef vector<pii> vii;
typedef vector<pll> vll;
typedef vector<int>::iterator vit;
typedef set<int>::iterator sit;
 
#define FAST             ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0)
#define endl             '\n'
#define loop(i,n)        for(int i=0;i<n;i++)
#define CASE_PRINT       cout<<"Case "<<C<<": "
#define CASE_PRINT2      cout<<"Case "<<C<<":"<<endl
#define ll               long long
#define ld               long double
#define Pi               2*acos(0.0) // acos(-1.0)
#define err              1e-9
 
#define PB push_back
#define F first
#define S second
#define MP make_pair
#define all(a) (a).begin(),(a).end()
#define mid(l,r) ((r+l)/2)
#define left(node) (node*2)
#define right(node) (node*2+1)
#define mx_int_prime 999999937
#define mem(a,b) memset(a, b, sizeof(a) )
#define gcd(a,b) __gcd(a,b)
#define sqr(a) ((a) * (a))
 
 
template < typename F, typename S >
ostream& operator << ( ostream& os, const pair< F, S > & p ) {
            return os << "(" << p.first << ", " << p.second << ")";
}
 
template < typename T >
ostream &operator << ( ostream & os, const vector< T > &v ) {
            os << "{";
                for(auto it = v.begin(); it != v.end(); ++it) {
                                if( it != v.begin() ) os << ", ";
                                        os << *it;
                                            }
                    return os << "}";
}
 
template < typename T >
ostream &operator << ( ostream & os, const set< T > &v ) {
            os << "[";
                for(auto it = v.begin(); it != v.end(); ++it) {
                                if( it != v.begin() ) os << ", ";
                                        os << *it;
                                            }
                    return os << "]";
}
 
template < typename T >
ostream &operator << ( ostream & os, const multiset< T > &v ) {
            os << "[";
                for(auto it = v.begin(); it != v.end(); ++it) {
                                if( it != v.begin() ) os << ", ";
                                        os << *it;
                                            }
                    return os << "]";
}
 
template < typename F, typename S >
ostream &operator << ( ostream & os, const map< F, S > &v ) {
            os << "[";
                for(auto it = v.begin(); it != v.end(); ++it) {
                                if( it != v.begin() ) os << ", ";
                                        os << it -> first << " = " << it -> second ;
                                            }
                    return os << "]";
}
 
#define dbg(args...) do {cerr << #args << " : "; faltu(args); } while(0)
 
void faltu () {
            cerr << endl;
}
 
template <typename T>
void faltu( T a[], int n ) {
            for(int i = 0; i < n; ++i) cerr << a[i] << ' ';
                cerr << endl;
}
 
template <typename T, typename ... hello>
void faltu( T arg, const hello &... rest) {
            cerr << arg << ' ';
                faltu(rest...);
}
 
const double PI = acos(-1.0);
const double eps = 1e-9;
const int inf = 2000000000;
const ll infLL = 9000000000000000000;
#define MOD 1000000007
int dx[] = {0, 0, +1, -1, +1, +1, -1, -1};
int dy[] = {+1, -1, 0, 0, +1, -1, +1, -1};
 
const int mx = 1e5+123;
 
int main()
{
    string s;cin>>s;
    set<char>st;
    for(auto i : s)st.insert(i);
    int total = st.size();
    int l=0, r=0, len=1e9;
    st.clear();
 
    int strlen = (int)s.size();
    for(int i=1; i<strlen and l<strlen and r<strlen; i++)
    {
        if(s[l] == s[i] and i==l+1){l++;r++;st.insert(s[i]);}
        else
        {
            r++;
            st.insert(s[i]);
        }
 
        if(st.size() == total)
        {
            len = min(len,(r-l+1));
            l = i+1;
            r = i+1;
            st.clear();
        }///dbg(l,r,st.size());
    }
 
    cout<<len<<endl;
}