Team

Source: Codeforces

Version: Phuoc Hung OJ Extended

Problem Statement

For each of n problems, three teammates vote 0 or 1. Count problems with at least two affirmative votes.

Input

n in [1,1000], followed by n triples of 0/1 votes.

Output

The count of triples whose sum is at least 2.

Subtasks

• Subtask 1 (20%): $n\le5$.
• Subtask 2 (30%): $n\le100$.
• Subtask 3 (50%): $n\le1000$.

Examples

Example 1

Input

3
1 1 0
1 1 1
1 0 0

Output

2

Explanation

The first two triples have >=2 ones; the third does not.