def getLongestSubsequence(arr):
    n = len(arr)
    max_len = 0
    
    for i in range(n):
        for j in range(i, n):
            x, y = arr[i], arr[j]
            length = 0
            expect_x = True
            
            for k in range(i, n):
                if (expect_x and arr[k] == x) or (not expect_x and arr[k] == y):
                    length += 1
                    expect_x = not expect_x
            
            max_len = max(max_len, length)
    
    return max_len

arr = list(map(int, input().split(',')))
result = getLongestSubsequence(arr)
print(result) 

#include <bits/stdc++.h>
using namespace std;
#define ll long long
ll n;
ll minFreq=0;
unordered_map<ll,pair<ll,ll>> keyVal;
unordered_map<ll,list<ll>> freqList;
unordered_map<ll,list<ll>::iterator> pos;
ll get(ll key) 
{
    if(keyVal.find(key) == keyVal.end()) return -1;
    freqList[keyVal[key].second].erase(pos[key]);
    keyVal[key].second++;
    freqList[keyVal[key].second].push_back(key);
    pos[key] = --freqList[keyVal[key].second].end();
    if(freqList[minFreq].empty()) minFreq++;
    return keyVal[key].first;
}
void put(ll key, ll value) 
{
    if(!n) return;
    if(keyVal.find(key) != keyVal.end()) 
    {
        keyVal[key].first = value;
        freqList[keyVal[key].second].erase(pos[key]);
        keyVal[key].second++;
        freqList[keyVal[key].second].push_back(key);
        pos[key] = --freqList[keyVal[key].second].end();
        if(freqList[minFreq].empty())
            minFreq++;
        return;
    }
    if(keyVal.size()==n) 
    {
        ll delKey = freqList[minFreq].front();
        keyVal.erase(delKey);
        pos.erase(delKey);
        freqList[minFreq].pop_front();
    }
    keyVal[key] = {value,1};
    freqList[1].push_back(key);
    pos[key] = --freqList[1].end();
    minFreq = 1;
}
signed main() 
{
    cin>>n;
    ll q; cin>>q;
    while(q--)
    {
        ll x,y,z; cin>>x>>y>>z;
        if(x==1) cout<<get(y)<<" ";
        else put(y,z);
    }
    return 0;
}

WITH june_events AS (
  SELECT *
  FROM events
  WHERE dt >= '2022-06-01' AND dt < '2022-07-01'
),
grouped_data AS (
  SELECT 
    mime,
    GROUP_CONCAT(DISTINCT SUBSTRING_INDEX(filename, '.', -1) ORDER BY SUBSTRING_INDEX(filename, '.', -1) SEPARATOR ', ') AS extension,
    COUNT(*) AS files,
    SUM(filesize) / (1024 * 1024) AS total_mib
  FROM june_events
  GROUP BY mime
)
SELECT 
  mime,
  extension,
  files,
  CASE 
    WHEN total_mib >= 1024 THEN CONCAT(ROUND(total_mib / 1024, 2), ' GiB')
    ELSE CONCAT(ROUND(total_mib, 2), ' MiB')
  END AS total
FROM grouped_data
ORDER BY total_mib DESC;

def inject_in_case(s, k):
    for i in range(len(s)):
        if k >= s[i]:
            return s[:i] + k + s[i:]
    return s + k
s = input().strip()
k = input().strip()

if len(k) == 1:
    result = inject_in_case(s, k)
    print(result)