#include<bits/stdc++.h>
#define LL long long
#define DB double
#define MOD 1000000007
#define ls(x) (x << 1)
#define rs(x) (x << 1 | 1)
#define lowbit(x) ((-x) & x)
#define MP make_pair
#define MT make_tuple
#define VI vector<int>
#define VL vector<LL>
#define VII VI::iterator
#define VLI VL::iterator
#define all(x) x.begin(), x.end()
#define EB emplace_back
#define PII pair<int, int>
#define SI set<int>
#define SII SI::iterator
#define fi first
#define se second
using namespace std;
template<typename T> void chkmn(T &a, const T b) { (a > b) && (a = b); }
template<typename T> void chkmx(T &a, const T b) { (a < b) && (a = b); }
void Inc(int &a, const int &b) { ((a += b) >= MOD) && (a -= MOD); }
void Dec(int &a, const int &b) { ((a -= b) < 0) && (a += MOD); }
void Mul(int &a, const int &b) { a = 1LL * a * b % MOD; }
void Sqr(int &a) { a = 1LL * a * a % MOD; }
int inc(const int &a, const int &b) { return (a + b >= MOD) ? a + b - MOD : a + b; }
int dec(const int &a, const int &b) { return (a - b < 0) ? a - b + MOD : a - b; }
int mul(const int &a, const int &b) { return 1LL * a * b % MOD; }
int sqr(const int &a) { return 1LL * a * a % MOD; }
int qwqmi(int x, int k = MOD - 2)
{
	int res = 1;
	while(k)
	{
		if(k & 1) Mul(res, x);
		k >>= 1, Sqr(x);
	}
	return res;
}
const int N = 5e4 + 5;
int n, K, m;
char ch[N];
int f[2][8][512], ans;
int now = 0, lst = 1;
// optimize
bool vis[26];
int _y, _T;
struct Saya
{
	int a[N], b[N];
	void Decode(int p, int x, int S)
	{
		a[p - 1] = p - 1 - x;
		for(int i = 0; i < K; ++i)
		{
			if(p + i > n) break;
			a[p + i] = a[p + i - 1] + ((S >> (K + i)) & 1);
		}
		for(int i = 1; i <= K; ++i)
		{
			if(p - 1 - i <= 0) continue;
			a[p - 1 - i] = a[p - i] - ((S >> (K - i)) & 1);
		}
	}
	inline int Encode(int p)
	{
		int res = 0;
		for(int i = max(0, p - K); i < min(n, p + K); ++i)
			if(b[i + 1] - b[i] == 1)
				res |= (1 << (i - (p - K)));
		return res;
	}
	inline void Trans(int S, int p, int x, char c)
	{
		for(int i = max(1, p - K); i <= min(n, p + K); ++i)
			b[i] = max(b[i - 1], max(a[i], a[i - 1] + (c == ch[i])));
		int T = Encode(p);
		int y = p - b[p];
		if(y > K) return;
		Inc(f[now][y][T], f[lst][x][S]);
		if(!vis[c - 'A']) _y = y, _T = T;
	}
}aya;
int main()
{
	scanf("%s", ch + 1);
	scanf("%d", &K);
	if(K == 0) return puts("1"), 0;
	n = strlen(ch + 1);
	m = 2 * K;
	now = 0, lst = 1;
	f[0][0][0] = 1;
	for(int i = 1; i <= n; ++i)
	{
		swap(lst, now);
		memset(vis, 0, sizeof(vis));
		for(int j = max(1, i - K); j <= min(n, i + K); ++j)
			vis[ch[j] - 'A'] = 1;
		for(int x = 0; x <= K; ++x)
			for(int S = 0; S < (1 << m); ++S)
				f[now][x][S] = 0;
		for(int x = 0; x <= K; ++x)
			for(int S = 0; S < (1 << m); ++S)
				if(f[lst][x][S])
				{
					_y = -1;
					aya.Decode(i, x, S);
					for(int c = 0; c < 26; ++c)
					{
						if(!vis[c] && _y != -1)
						{
							Inc(f[now][_y][_T], f[lst][x][S]);
							continue;
						}
						aya.Trans(S, i, x, c + 'A');
					}
				}
	}
	for(int x = 0; x <= K; ++x)
		for(int S = 0; S < (1 << m); ++S)
			Inc(ans, f[now][x][S]);
	printf("%d\n", ans);
	return 0;
}