#include #include #include #include #include #include #include #include //#include #include #define FOR(i,a,b) for (int i=(a);i<(b);i++) #define RFOR(i,a,b) for (int i=(b)-1;i>=(a);i--) #define REP(i,n) for (int i=0;i<(n);i++) #define RREP(i,n) for (int i=(n)-1;i>=0;i--) #define SWAP(a,b) (a ^= b,b = a ^ b,a ^= b) #define swap(type,a,b) do{type _c;_c=a;a=b;b=_c;}while(0) using namespace std; typedef long long int lint; template ostream& operator << (ostream& ostr, const vector<_Ty>& v) { if (v.empty()) { cout << "{ }"; return ostr; } cout << "{" << v.front(); for (auto itr = ++v.begin(); itr != v.end(); itr++) { cout << ", " << *itr; } cout << "}"; return ostr; } int yuki0045() { int n, tmp; cin >> n; int* v = new int[n + 3]; v[0] = v[1] = v[2] = 0; for (int i = 0; i < n; i++) { cin >> tmp; v[i + 3] = max(v[i], v[i + 1]) + tmp; } cout << max(v[n + 1], v[n + 2]) << endl; delete[] v; return 0; } int main() { //clock_t start, end; //start = clock(); yuki0045(); //end = clock(); //printf("%d msec.\n", end - start); return 0; }