First Negative Value Position

Source: Phước Hưng OJ

Version: Phuoc Hung OJ Extended

Problem Statement

Find the first 1-based index containing a negative value among $n$ integers, or print -1 if none exists. Use break to stop after the first match.

Input

First $n$, followed by exactly $n$ integers in $[-10^6,10^6]$.

Output

The first negative position, or -1.

Subtasks

• Subtask 1 (20%): $0\le n\le 8$; $-10^6\le a_i\le10^6$.

• Subtask 2 (30%): $0\le n\le 1000$; $-10^6\le a_i\le10^6$.

• Subtask 3 (50%): $0\le n\le 100000$; $-10^6\le a_i\le10^6$.

Examples

Example 1

Input:

4
0 9 7 -1

Output:

4

Explanation:

Scan left to right; the first negative value determines the reported position.

Example 2

Input:

3
1 2 3

Output:

-1

Explanation:

Scan left to right; the first negative value determines the reported position.