Valid Sessions Before Stop

Source: Phước Hưng OJ

Version: Phuoc Hung OJ Extended

Problem Statement

A stream consists of pairs (k, x). For k=1, count the attempt only if $0\le x\le10$. Code k=0 terminates the stream and is not counted. The final pair is 0 0. Both endpoint values 0 and 10 are valid.

Input

A sequence of integer pairs k x, k in {0,1}. The last pair is 0 0; all previous codes are 1. An operand of code 1 may be outside the accepted range.

Output

Print the number of code-1 pairs whose operand belongs to the closed interval [0,10].

Subtasks

• Subtask 1 (20%): At most 5 pairs including stop; $|x|\le10$.
• Subtask 2 (30%): At most 100 pairs including stop; $|x|\le100$.
• Subtask 3 (50%): At most 10000 pairs including stop; $|x|\le10^6$.

Examples

Example 1

Input

1 5
1 11
1 0
0 0

Output

2

Explanation

5 and 0 belong to [0,10]; 11 does not. The terminating pair is excluded.

Example 2

Input

1 10
1 -1
0 0

Output

1

Explanation

10 is valid at the upper endpoint, -1 is not, so the answer is 1.