https://www.acmicpc.net/problem/13301
# 타일 장식물 import sys input = sys.stdin.readline N = int(input()) dp = [0] * 81 # 1<= N <= 80 dp[1] = 4 dp[2] = 6 for i in range(3, N + 1): dp[i] = dp[i - 1] + dp[i - 2] print(dp[N])