#include <iostream> #include <vector> using namespace std; int main() { int n; cin >> n; if (n <= 0) { cout << 0 << endl; return 0; } if (n == 1 || n == 2) { cout << 10000 << endl; return 0; } vector<long long> sequence(n + 1); sequence[1] = 10000; sequence[2] = 10000; for (int i = 3; i <= n; i++) { if (i % 2 == 1) { // 奇数位置: 前一项减去(i-1)/2 sequence[i] = sequence[i-1] - (i - 1) / 2; } else { // 偶数位置: 前一项减去(i-2)/2 sequence[i] = sequence[i-1] - (i - 2) / 2; } } cout << sequence[n] << endl; return 0; }