FAST_IO = 0

if FAST_IO:

    import io, sys, atexit

    rr = iter(sys.stdin.read().splitlines()).__next__

    sys.stdout = _OUTPUT_BUFFER = io.BytesIO()

    @atexit.register

    def write():

        sys.__stdout__.write(_OUTPUT_BUFFER.getvalue())

else:

    rr = raw_input

rri = lambda: int(rr())

rrm = lambda: list(map(int, rr().split()))

rrmm = lambda n: [rrm() for _ in range(n)]



####



def solve(K, S):

    MOD = 10 ** 9 + 7

    N = len(S)

    N2 = N + K



    BIG =N2

    fac = [1, 1]

    for x in range(2, BIG+1):

        fac.append(fac[-1] * x  %MOD)

    inv = [1] * (BIG + 1)

    inv[BIG] = pow(fac[-1], MOD-2, MOD)

    for x in range(BIG-1, -1, -1):

        inv[x] = inv[x+1] * (x+1) % MOD



    def binom(n, k):

        ans = fac[n]

        ans *= inv[n-k]

        ans %= MOD

        

        ans *= inv[k]

        ans %= MOD

        return ans



    pow25 = [1]

    for x in range(1, BIG + 1):

        pow25.append(pow25[-1] * 25  %MOD)



    ans = 0

    for n in range(N, N2 + 1):

        ans += binom(N2, n)   * pow25[N2- n] % MOD

        ans %= MOD

    return ans



print(solve(rri(), rr()))

MOD = 10 ** 9 + 7

K = int(eval(input()))

M = len(eval(input()))

N = M + K



pow25 = [1] * (N + 1)

fac = [1] * (N + 1)

inv = [1] * (N + 1)

for x in range(1, N + 1):

    fac[x] = fac[x - 1] * x % MOD

    pow25[x] = pow25[x - 1] * 25 % MOD

inv[N] = pow(fac[N], MOD-2, MOD)

for x in range(N - 1, -1, -1):

    inv[x] = inv[x + 1] * (x + 1) % MOD



def binom(n, k):

    return fac[n] * inv[n - k] % MOD * inv[k] % MOD



ans = 0

for k in range(M, N + 1):

    ans += binom(N, k) * pow25[N - k] % MOD

    ans %= MOD

print(ans)

FAST_IO = 0
if FAST_IO:
    import io, sys, atexit

    rr = iter(sys.stdin.read().splitlines()).__next__
    sys.stdout = _OUTPUT_BUFFER = io.BytesIO()

    @atexit.register
    def write():
        sys.__stdout__.write(_OUTPUT_BUFFER.getvalue())

else:
    rr = raw_input
rri = lambda: int(rr())
rrm = lambda: list(map(int, rr().split()))
rrmm = lambda n: [rrm() for _ in range(n)]
####
def solve(K, S):
    MOD = 10**9 + 7
    N = len(S)
    N2 = N + K
    BIG = N2
    fac = [1, 1]
    for x in range(2, BIG + 1):
        fac.append(fac[-1] * x % MOD)
    inv = [1] * (BIG + 1)
    inv[BIG] = pow(fac[-1], MOD - 2, MOD)
    for x in range(BIG - 1, -1, -1):
        inv[x] = inv[x + 1] * (x + 1) % MOD

    def binom(n, k):
        ans = fac[n]
        ans *= inv[n - k]
        ans %= MOD
        ans *= inv[k]
        ans %= MOD
        return ans

    pow25 = [1]
    for x in range(1, BIG + 1):
        pow25.append(pow25[-1] * 25 % MOD)
    ans = 0
    for n in range(N, N2 + 1):
        ans += binom(N2, n) * pow25[N2 - n] % MOD
        ans %= MOD
    return ans


print(solve(rri(), rr()))

MOD = 10**9 + 7
K = int(eval(input()))
M = len(eval(input()))
N = M + K
pow25 = [1] * (N + 1)
fac = [1] * (N + 1)
inv = [1] * (N + 1)
for x in range(1, N + 1):
    fac[x] = fac[x - 1] * x % MOD
    pow25[x] = pow25[x - 1] * 25 % MOD
inv[N] = pow(fac[N], MOD - 2, MOD)
for x in range(N - 1, -1, -1):
    inv[x] = inv[x + 1] * (x + 1) % MOD


def binom(n, k):
    return fac[n] * inv[n - k] % MOD * inv[k] % MOD


ans = 0
for k in range(M, N + 1):
    ans += binom(N, k) * pow25[N - k] % MOD
    ans %= MOD
print(ans)

-FAST_IO = 0 -if FAST_IO: -    import io, sys, atexit - -    rr = iter(sys.stdin.read().splitlines()).__next__ -    sys.stdout = _OUTPUT_BUFFER = io.BytesIO() - -    @atexit.register -    def write(): -        sys.__stdout__.write(_OUTPUT_BUFFER.getvalue()) - -else: -    rr = raw_input -rri = lambda: int(rr()) -rrm = lambda: list(map(int, rr().split())) -rrmm = lambda n: [rrm() for _ in range(n)] -#### -def solve(K, S): -    MOD = 10**9 + 7 -    N = len(S) -    N2 = N + K -    BIG = N2 -    fac = [1, 1] -    for x in range(2, BIG + 1): -        fac.append(fac[-1] * x % MOD) -    inv = [1] * (BIG + 1) -    inv[BIG] = pow(fac[-1], MOD - 2, MOD) -    for x in range(BIG - 1, -1, -1): -        inv[x] = inv[x + 1] * (x + 1) % MOD - -    def binom(n, k): -        ans = fac[n] -        ans *= inv[n - k] -        ans %= MOD -        ans *= inv[k] -        ans %= MOD -        return ans - -    pow25 = [1] -    for x in range(1, BIG + 1): -        pow25.append(pow25[-1] * 25 % MOD) -    ans = 0 -    for n in range(N, N2 + 1): -        ans += binom(N2, n) * pow25[N2 - n] % MOD -        ans %= MOD -    return ans +MOD = 10**9 + 7 +K = int(eval(input())) +M = len(eval(input())) +N = M + K +pow25 = [1] * (N + 1) +fac = [1] * (N + 1) +inv = [1] * (N + 1) +for x in range(1, N + 1): +    fac[x] = fac[x - 1] * x % MOD +    pow25[x] = pow25[x - 1] * 25 % MOD +inv[N] = pow(fac[N], MOD - 2, MOD) +for x in range(N - 1, -1, -1): +    inv[x] = inv[x + 1] * (x + 1) % MOD -print(solve(rri(), rr())) +def binom(n, k): +    return fac[n] * inv[n - k] % MOD * inv[k] % MOD + + +ans = 0 +for k in range(M, N + 1): +    ans += binom(N, k) * pow25[N - k] % MOD +    ans %= MOD +print(ans)