n = int(input()) # 动规解法 if n < 3: print(n) else: dp = [0] * (n+1) dp[1], dp[2] = 1, 2 for i in range(3, n + 1): dp[i] = dp[i-2] + dp[i-1] print(dp[n]) # 循环相加解法 if n < 3: print(n) else: k1, k2 = 1, 2 i = 3 while i <= n: k = k1 + k2 ...