Switch Inside a Loop

Source: Phước Hưng OJ

Version: Phuoc Hung OJ Extended

Problem Statement

Process n codes 0..3 left to right. Add 1, 2, or 3 for corresponding codes; the first 0 terminates processing without contributing. If no 0 occurs, process all n. A switch-case break does not exit the surrounding loop.

Input

First n (0<=n<=10000), then exactly n codes from [0,3].

Output

Print the sum of codes preceding the first zero.

Subtasks

• Subtask 1 (20%): $0\le n\le 10$; $0\le x_i\le3$.

• Subtask 2 (30%): $0\le n\le 1000$; $0\le x_i\le3$.

• Subtask 3 (50%): $0\le n\le 10000$; $0\le x_i\le3$.

Examples

Example 1

Input:

5
1 2 0 3 3

Output:

3

Explanation:

Only codes before the first zero contribute. Result: 3.

Example 2

Input:

4
1 2 3 1

Output:

7

Explanation:

Only codes before the first zero contribute. Result: 7.

Example 3

Input:

0

Output:

0

Explanation:

Only codes before the first zero contribute. Result: 0.