N = int(input())
mod = 998244353
DP = [0]*(N+1)
DP[0]=1
for _ in range(N):
    NDP = [0]*(N+1)
    for i in range(N):
      if DP[i]>0:
        NDP[i]=(NDP[i]+DP[i]*25)%mod
        NDP[i+1]=(NDP[i+1]+DP[i])%mod
    DP = NDP
ans = 0
for i in range(N+1):
    ans+=DP[i]*(i//3)
print(ans%mod)