#include <stdio.h> int main() { int n; scanf("%d", &n); int dp[n + 1]; int cost[n]; for (int i = 0; i < n; i++) { scanf("%d", &cost[i]); } dp[0] = 0; dp[1] = 0; for (int j = 2; j <= n; j++) { dp[j] = dp[j - 1] + cost[j - 1] < dp[j - 2] + cost[j - 2] ? dp[j - 1] + cost[j - 1] : dp[j - 2] + cost[j - 2]; } printf("%d",dp[n]); return 0; }