/*
ID: lsswxr1
PROG: calfflac
LANG: C++
*/
#include <iostream>
#include <vector>
#include <map>
#include <list>
#include <set>
#include <deque>
#include <stack>
#include <queue>
#include <algorithm>
#include <cmath>
#include <cctype>
#include <cstdio>
#include <iomanip>
#include <cmath>
#include <cstdio>
#include <string>
#include <cstring>
#include <fstream>
using namespace std;///宏定义
const int  INF = 1000000000;
const int MAXN = 20015;
const int maxn = MAXN;
///全局变量 和 函数#define USACO
#ifdef USACO
#define cin fin
#define cout fout
#endif
//
char src[maxn], txt[maxn];
int reflect[maxn];
int cntTxt, cntSrc;
int ans1, ans2, anslen;
inline bool ok(char s1, char s2)
{int a1 = s1 - 'a';int a2 = s1 - 'A';int b1 = s2 - 'a';int b2 = s2 - 'A';if (a1 == b1 || a1 == b2 || a2 == b1 || a2 == b2)return true;return false;
}
int main()
{
#ifdef USACO    ofstream fout ("calfflac.out");ifstream fin ("calfflac.in");
#endif    ///变量定义string src_;cntSrc = 0;cntTxt = 0;while (getline(cin, src_)){int len = src_.length();for (int i = 0; i < len; i++){src[cntSrc] = src_[i];if ((src[cntSrc] >= 'a' && src[cntSrc] <= 'z') || (src[cntSrc] >= 'A' && src[cntSrc] <= 'Z') ){txt[cntTxt] = src[cntSrc];reflect[cntTxt] = cntSrc;cntTxt++;}cntSrc++;}src[cntSrc++] = '\n';}src[cntSrc] = '\0';bool flag;anslen = 1;for (int midpos = 0; midpos < cntTxt; midpos++){int maxlen = 0;//奇数int ll = midpos - 1;int rr = midpos + 1;maxlen = 1;while (ll >= 0 && rr < cntTxt){if (ok(txt[ll], txt[rr])){maxlen += 2;ll--;rr++;}elsebreak;}if (maxlen > anslen){anslen = maxlen;ans1 = reflect[ll + 1];ans2 = reflect[rr - 1];}//偶数ll = midpos - 1;rr = midpos;maxlen = 0;while (ll >= 0 && rr < cntTxt){if (ok(txt[ll], txt[rr])){maxlen += 2;ll--;rr++;}elsebreak;}if (maxlen > anslen){anslen = maxlen;ans1 = reflect[ll + 1];ans2 = reflect[rr - 1];}}cout << anslen << endl;for (int i = ans1; i <= ans2; i++){cout << src[i];}cout << endl;///结束return 0;
}