#include <bits/stdc++.h>
using namespace std;
const int N = 205;
const int mod = 10007;
void add(int &x, int y) {
  x += y;
  if (x >= mod) x -= mod;
}
int mul(int x, int y) { return x * y % mod; }
int pw(int x, int y) {
  int ret = 1;
  while (y) {
    if (y & 1) ret = mul(ret, x);
    x = mul(x, x);
    y >>= 1;
  }
  return ret;
}
namespace berlekamp_massey {
vector<int> bm(vector<int> x) {
  vector<int> rel, cur;
  int lf, ld;
  for (int i = 0; i < x.size(); ++i) {
    int sum = 0;
    for (int j = 0; j < cur.size(); ++j) add(sum, mul(x[i - j - 1], cur[j]));
    if (sum == x[i]) continue;
    if (!cur.size()) {
      cur.resize(i + 1);
      lf = i;
      ld = sum - x[i];
      add(ld, mod);
      continue;
    }
    int coef = mul(sum - x[i] + mod, pw(ld, mod - 2));
    vector<int> new_cur(i - lf - 1);
    new_cur.push_back(coef);
    for (int j = 0; j < rel.size(); ++j) {
      new_cur.push_back(mul(mod - rel[j], coef));
    }
    if (new_cur.size() < cur.size()) new_cur.resize(cur.size());
    for (int j = 0; j < cur.size(); ++j) add(new_cur[j], cur[j]);
    if (i - lf + rel.size() >= cur.size()) {
      rel = cur, lf = i, ld = sum - x[i];
      add(ld, mod);
    }
    cur = new_cur;
  }
  return cur;
}
int sz;
int a[5005], rel[5005], tmp[5005];
int ff[5005], gg[5005];
void mulmod(int *p, int *q) {
  for (int i = 0; i < sz + sz; ++i) tmp[i] = 0;
  for (int i = 0; i < sz; ++i)
    if (p[i]) {
      for (int j = 0; j < sz; ++j) {
        add(tmp[i + j], mul(p[i], q[j]));
      }
    }
  for (int i = sz + sz - 1; i >= sz; --i)
    if (tmp[i]) {
      for (int j = sz - 1; j >= 0; --j) {
        add(tmp[i - j - 1], mul(tmp[i], rel[j]));
      }
    }
  for (int i = 0; i < sz; ++i) p[i] = tmp[i];
}
int solve(vector<int> x, int n) {
  if (n < x.size()) return x[n];
  vector<int> cur = bm(x);
  sz = cur.size();
  for (int i = 0; i < sz; ++i) rel[i] = cur[i], a[i] = x[i];
  for (int i = 0; i < sz; ++i) ff[i] = gg[i] = 0;
  ff[0] = 1;
  if (sz > 1)
    gg[1] = 1;
  else
    gg[0] = rel[0];
  while (n) {
    if (n & 1) mulmod(ff, gg);
    mulmod(gg, gg);
    n >>= 1;
  }
  int ret = 0;
  for (int i = 0; i < sz; ++i) add(ret, mul(ff[i], a[i]));
  return ret;
}
}  // namespace berlekamp_massey
using namespace berlekamp_massey;
int n, m;
string s;
int f[805][N][N], ans[1405];
vector<int> g;
int main() {
  ios_base::sync_with_stdio(false);
  cin >> s >> n;
  m = s.size();
  s = '~' + s;
  f[0][0][0] = 1;
  int len = m + 1400 >> 1;
  for (int i = 1; i <= len; ++i) {
    for (int j = 0; j <= m; ++j) {
      for (int k = 0; k <= m; ++k) {
        if (f[i - 1][j][k] == 0) continue;
        if (j == m && k == m)
          add(f[i][j][k], mul(26, f[i - 1][j][k]));
        else if (j == m) {
          add(f[i][j][k], mul(25, f[i - 1][j][k]));
          add(f[i][j][k + 1], f[i - 1][j][k]);
        } else if (k == m) {
          add(f[i][j][k], mul(25, f[i - 1][j][k]));
          add(f[i][j + 1][k], f[i - 1][j][k]);
        } else {
          if (s[j + 1] == s[m + 1 - k - 1]) {
            add(f[i][j + 1][k + 1], f[i - 1][j][k]);
            add(f[i][j][k], mul(25, f[i - 1][j][k]));
          } else {
            add(f[i][j + 1][k], f[i - 1][j][k]);
            add(f[i][j][k + 1], f[i - 1][j][k]);
            add(f[i][j][k], mul(24, f[i - 1][j][k]));
          }
        }
      }
    }
  }
  for (int i = 0; i < 1400; ++i) {
    int l = m + i >> 1;
    for (int j = 0; j <= m; ++j) {
      for (int k = 0; k <= m; ++k) {
        if (j + k >= m) {
          if (m + i & 1)
            add(ans[i], mul(26, f[l][j][k]));
          else
            add(ans[i], f[l][j][k]);
        }
        if (j + k == m - 1) {
          if (m + i & 1) add(ans[i], f[l][j][k]);
        }
      }
    }
  }
  for (int i = 0; i < 1400; ++i) g.push_back(ans[i]);
  cout << solve(g, n) << '\n';
  return 0;
}
