import sys
input = sys.stdin.readline
from collections import *

N = int(input())
dp = [[0]*3 for _ in range(N+1)]
dp[0][0] = 1
MOD = 998244353

for _ in range(N):
    ndp = [[0]*3 for _ in range(N+1)]
    
    for i in range(N+1):
        ndp[i][0] += 25*dp[i][0]%MOD
        ndp[i][0] %= MOD
        ndp[i][1] += (25*dp[i][1]+dp[i][0])%MOD
        ndp[i][1] %= MOD
        ndp[i][2] += (25*dp[i][2]+dp[i][1])%MOD
        ndp[i][2] %= MOD
        
        if i+1<=N:
            ndp[i+1][0] += dp[i][2]
            ndp[i+1][0] %= MOD
    
    dp = ndp

ans = 0

for i in range(N+1):
    for j in range(3):
        ans += i*dp[i][j]
        ans %= MOD

print(ans)