import sys
from collections import defaultdict

MOD = 998244353

def main():
    N = int(sys.stdin.readline())

    prev_dp = [defaultdict(int) for _ in range(3)]
    prev_dp[0][0] = 1  # Initial state: 0 chars processed, state 0, k=0

    for _ in range(N):
        next_dp = [defaultdict(int) for _ in range(3)]
        for s in range(3):
            for k in prev_dp[s]:
                count = prev_dp[s][k]
                if count == 0:
                    continue
                if s == 0:
                    # Transition for choosing 'c'
                    next_s = 1
                    next_k = k
                    next_dp[next_s][next_k] = (next_dp[next_s][next_k] + count) % MOD
                    # Transition for others (25 possibilities)
                    next_dp[0][k] = (next_dp[0][k] + count * 25) % MOD
                elif s == 1:
                    # Transition for choosing 'o'
                    next_s = 2
                    next_k = k
                    next_dp[next_s][next_k] = (next_dp[next_s][next_k] + count) % MOD
                    # Transition for others (25 possibilities)
                    next_dp[1][k] = (next_dp[1][k] + count * 25) % MOD
                elif s == 2:
                    # Transition for choosing 'n'
                    next_s = 0
                    next_k = k + 1
                    next_dp[next_s][next_k] = (next_dp[next_s][next_k] + count) % MOD
                    # Transition for others (25 possibilities)
                    next_dp[2][k] = (next_dp[2][k] + count * 25) % MOD
        prev_dp = next_dp

    result = 0
    for s in range(3):
        for k in prev_dp[s]:
            result = (result + k * prev_dp[s][k]) % MOD
    print(result)

if __name__ == "__main__":
    main()