MOD = 10 ** 9 + 7


def solveBrute(K, S):
    N = len(S)
    dp = [0] * (N + 1)
    dp[0] = 1
    for i in range(N + K):
        # dp[j] currently counts all strings of length i which contains S[:j] as a subsequence

        nextDp = [0] * (N + 1)
        for j in range(N):
            nextDp[j] += dp[j] * 25  # don't extend subsequence
            nextDp[j + 1] += dp[j]  # extend subsequence
        nextDp[N] += dp[N] * 26  # max len subsequence can't be extended anymore

        dp = nextDp
        for j in range(N + 1):
            dp[j] %= MOD
        # print(dp)

    return dp[N]