#include <bits/stdc++.h>   using namespace std;   const long long MOD = 1000000007;   const long long SIZE = 100000;   const int INF = 0x3f3f3f3f;   const long long LL_INF = 0x3f3f3f3f3f3f3f3f;   const long double PI = acos(-1);   const long long MAXN = numeric_limits<long long>::max();   template <class T>   T maxT(T a, T b) {     return (a > b ? a : b);   }   template <class T>   T minT(T a, T b) {     return (a < b ? a : b);   }   template <class T>   void setmin(T &a, T b) {     a = (a > b ? a : b);   }   template <class T>   void setmax(T &a, T b) {     a = (a < b ? a : b);   }   void fileio() {     freopen( input.txt ,  r , stdin);     freopen( output.txt ,  w , stdout);     freopen( debug.txt ,  w , stderr);   }   void ofileio() {     freopen( input.txt ,  r , stdin);     freopen( output.txt ,  w , stdout);   }   void clock_out() {     cerr <<   nTime Elapsed :   << 1.0 * clock() / CLOCKS_PER_SEC <<   s n ;   }   void debug_out() { cerr << endl; }   template <typename Head, typename... Tail>   void debug_out(Head H, Tail... T) {     cerr <<     << H;     debug_out(T...);   }   void solve() {     string s;     cin >> s;     string temp =   ;     vector<int> cnt;     int c = 1;     temp += s[0];     for (int i = 1; i < s.size(); i++) {       if (s[i] == s[i - 1]) {         c++;       } else {         temp += s[i];         cnt.push_back(c);         c = 1;       }     }     cnt.push_back(c);     string w = temp;     reverse((w).begin(), (w).end());     if (w != temp) {       cout << 0;       return;     } else {       int pos = (cnt.size()) / 2;       for (long long i = 0; i < pos; i++) {         if ((cnt[i] + cnt[cnt.size() - i - 1]) < 3) {           cout << 0;           return;         }       }       if (cnt[pos] >= 2)         cout << cnt[pos] + 1;       else         cout << 0;       return;     }   }   int main() {     ios_base::sync_with_stdio(false), cin.tie(0), cout.tie(0);     srand(time(NULL));     1;     long long t = 1;     while (t--) {       solve();     }     1;     return 0;   }   