import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.AbstractMap;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.Stack;
import java.util.TreeMap;


public class Main {
	
	public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        MyInput in = new MyInput(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        
        Solver solver = new Solver();
        solver.solve(1, in, out);
        
        out.close();
    }
    
    // ======================================================================
    static class Solver {
    	public void solve(int testNumber, MyInput in, PrintWriter out) {
    		String S = in.nextString();
    		char[] c = null;
    		char[] sv = new char[S.length()];
    		boolean f = true;
			sv[0] = S.charAt(0);
    		for(int i = 1; i < S.length(); i++) {
    			sv[i] = S.charAt(i);
    			if(sv[i] != sv[i-1])	f = false;
    		}
    		if(f) {
    			out.println(0);
    			return;
    		}
    		int ans = 999999999;
    		int cnt;
    		char key;
    		for(int i = 0; i < ('z' - 'a') + 1; i++) {
        		c = Arrays.copyOf(sv, sv.length);
    			for(int k=c.length; k > 0; k--) {
        			cnt = 0;
	    			for(int j=0; j < k; j++) {
	    				key = (char)('a' + i);
	    				if(j==0 && c[j] == key) {
	    					cnt++;
//	    					out.println("k = " + k + "  c[" + j 
//	    							+ "] = " + c[j] + "  cnt = " + cnt);
	    				} else if(j > 0 && c[j] == key) {
	    					if(c[j-1] == key) {
	    						cnt++;
	    					} else {
	    						cnt += 2;
	    						c[j-1] = key;
	    					}
	    					if(j == k-1)	cnt--;
//	    					out.println("k = " + k + "  c[" + (j-1) 
//	    							+ "] = " + c[j-1] + "  c[" + j 
//	    							+ "] = " + c[j] + "  cnt = " + cnt);
	    				}
	    			}
    				if(cnt >= k-1) {
    					ans = Math.min(ans, c.length - k + 1);
//    					out.println("k = " + k + "  cnt = " + cnt + "  -->  ans = " + ans);
    					break;
    				}
    			}
    		}
   			out.println(ans);
        }
    }
    // ======================================================================
    static class Pair<K, V> extends AbstractMap.SimpleEntry<K, V> {
        /** serialVersionUID. */
        private static final long serialVersionUID = 6411527075103472113L;

        public Pair(final K key, final V value) {
            super(key, value);
        }
        public String getString() {
            return "[" + getKey() + "] [" + getValue() + "]";
        }
     }    
    static class MyInput {
        private final BufferedReader in;
        private static int pos;
        private static int readLen;
        private static final char[] buffer = new char[1024 * 8];
        private static char[] str = new char[500 * 8 * 2];
        private static boolean[] isDigit = new boolean[256];
        private static boolean[] isSpace = new boolean[256];
        private static boolean[] isLineSep = new boolean[256];
 
        static {
            for (int i = 0; i < 10; i++) {
                isDigit['0' + i] = true;
            }
            isDigit['-'] = true;
            isSpace[' '] = isSpace['\r'] = isSpace['\n'] = isSpace['\t'] = true;
            isLineSep['\r'] = isLineSep['\n'] = true;
        }
 
        public MyInput(InputStream is) {
            in = new BufferedReader(new InputStreamReader(is));
        }
 
        public int read() {
            if (pos >= readLen) {
                pos = 0;
                try {
                    readLen = in.read(buffer);
                } catch (IOException e) {
                    throw new RuntimeException();
                }
                if (readLen <= 0) {
                    throw new MyInput.EndOfFileRuntimeException();
                }
            }
            return buffer[pos++];
        }
 
        public int nextInt() {
            int len = 0;
            str[len++] = nextChar();
            len = reads(len, isSpace);
            int i = 0;
            int ret = 0;
            if (str[0] == '-') {
                i = 1;
            }
            for (; i < len; i++) ret = ret * 10 + str[i] - '0';
            if (str[0] == '-') {
                ret = -ret;
            }
            return ret;
        }
 
        public long nextLong() {
            int len = 0;
            str[len++] = nextChar();
            len = reads(len, isSpace);
            int i = 0;
            long ret = 0L;
            if (str[0] == '-') {
                i = 1;
            }
            for (; i < len; i++) ret = ret * 10 + str[i] - '0';
            if (str[0] == '-') {
                ret = -ret;
            }
            return ret;
        }
 
        public String nextString() {
        	String ret = new String(nextDChar()).trim();
            return ret;
        }
 
        public char[] nextDChar() {
            int len = 0;
            len = reads(len, isSpace);
            char[] ret = new char[len + 1];
            for (int i=0; i < len; i++)		ret[i] = str[i];
            ret[len] = 0x00;
            return ret;
        }
 
        public char nextChar() {
            while (true) {
                final int c = read();
                if (!isSpace[c]) {
                    return (char) c;
                }
            }
        }
 
        int reads(int len, boolean[] accept) {
            try {
                while (true) {
                    final int c = read();
                    if (accept[c]) {
                        break;
                    }
                    if (str.length == len) {
                        char[] rep = new char[str.length * 3 / 2];
                        System.arraycopy(str, 0, rep, 0, str.length);
                        str = rep;
                    }
                    str[len++] = (char) c;
                }
            } catch (MyInput.EndOfFileRuntimeException e) {
            }
            return len;
        }
 
        static class EndOfFileRuntimeException extends RuntimeException {
        }
    }
}


Measured memory_bytes: 21584