C++ :

#include <iostream>
using namespace std;
int main() {
    int n;
    cin >> n;
    int arr[100];
    int index = -1;
    for (int i = 0; i < n; ++i) {
        cin >> arr[i];
        if (index == -1 && arr[i] < 0) {
            index = i;
        }
    }
    cout << index << endl;
    return 0;
}