func_code_string: #include <bits/stdc++.h>   using namespace std;   inline void proc_status() {     ifstream t( /proc/self/status );     cerr << string(istreambuf_iterator<char>(t), istreambuf_iterator<char>())          << endl;   }   template <typename T>   inline bool chkmin(T &a, const T &b) {     return a > b ? a = b, 1 : 0;   }   template <typename T>   inline bool chkmax(T &a, const T &b) {     return a < b ? a = b, 1 : 0;   }   template <typename T>   inline T read() {     register T sum(0), fg(1);     register char ch(getchar());     for (; !isdigit(ch); ch = getchar())       if (ch ==  - ) fg = -1;     for (; isdigit(ch); ch = getchar()) sum = sum * 10 -  0  + ch;     return sum * fg;   }   const int MOD = (int)1e9 + 7;   const int MAXN = (int)1e6;   int n;   char s0[MAXN + 5];   inline void input() { scanf( %s , s0 + 1), n = strlen(s0 + 1); }   namespace PAM {   const int MAX_NODE = MAXN * 2, alpha = 26;   int fail[MAX_NODE + 5], trans[MAX_NODE + 5][alpha], nxt[MAX_NODE + 5], cnt;   int len[MAX_NODE + 5], delta[MAX_NODE + 5];   int rt0, rt1, lst;   int S[MAX_NODE + 5], N = 0;   inline void init() {     S[0] = -1;     cnt = 1, lst = 0;     memset(trans[0], 0, sizeof trans[0]);     memset(trans[1], 0, sizeof trans[1]);     len[0] = 0, len[1] = -1;     fail[0] = 1;   }   inline int new_node(int l) {     len[++cnt] = l;     fail[cnt] = 0;     memset(trans[cnt], 0, sizeof trans[cnt]);     return cnt;   }   inline int extend(int ch) {     int p = lst;     S[++N] = ch;     while (S[N - len[p] - 1] != S[N]) p = fail[p];     int np = -1;     if (!trans[p][ch]) {       np = new_node(len[p] + 2);       int t = fail[p];       while (S[N - len[t] - 1] != S[N]) t = fail[t];       fail[np] = trans[t][ch];       delta[np] = len[np] - len[fail[np]];       nxt[np] = delta[np] == delta[fail[np]] ? nxt[fail[np]] : fail[np];       trans[p][ch] = np;     } else       np = trans[p][ch];     return lst = np;   }   }  // namespace PAM   inline void solve() {     static int s[MAXN + 5];     for (int i = 1; i <= n / 2; ++i) {       s[i * 2 - 1] = s0[i] -  a ;       s[i * 2] = s0[n - i + 1] -  a ;     }     static int nd[MAXN + 5];     PAM::init();     for (int i = 1; i <= n; ++i) nd[i] = PAM::extend(s[i]);     static int f[MAXN + 5], g[MAXN + 5];     f[0] = 1;     for (int i = 1; i <= n; ++i)       for (int p = nd[i]; p; p = PAM::nxt[p]) {         g[p] = f[i - PAM::len[PAM::nxt[p]] - PAM::delta[p]];         if (PAM::delta[p] == PAM::delta[PAM::fail[p]])           (g[p] += g[PAM::fail[p]]) %= MOD;         if (i % 2 == 0) (f[i] += g[p]) %= MOD;       }     printf( %d n , (f[n] + MOD) % MOD);   }   int main() {     input();     solve();     return 0;   }   