#include #include #include #include #include #include using namespace std; int nums[10001] = { }; int n = 0; void dfs(int x, int times) { if (x > n || x < 1 || nums[x] != 0) { return; } nums[x] = ++times; /* cout << "nums:" << x << " " << times << endl; cout<> k) % 2 == 1) { count++; } } dfs(x + count, times); dfs(x - count, times); } int main() { cin >> n; dfs(1, 0); if (nums[n] != 0) { cout << nums[n] << endl; } else { cout << -1 << endl; } return 0; }