Team

## 题目要求 三位选手要去参加编程竞赛，比赛共有N道题目，他们商定: 对于每一道题目，只有两位及以上的选手确认找到解法时才做。 试问，他们一共能做多少题? ### 输入格式 第一行一个整数N，表示题目的数量。 第二行到第N+1行，每行三个整数(0或者1)，其中0表示这位选手无法解出此题，1表示这位选手想到了解法。 ### 输出格式 一行，一个整数，表示他们所能做的题目的数量。 感谢@PC_DOS 提供翻译

One day three best friends Petya, Vasya and Tonya decided to form a team and take part in programming contests. Participants are usually offered several problems during programming contests. Long before the start the friends decided that they will implement a problem if at least two of them are sure about the solution. Otherwise, the friends won't write the problem's solution. This contest offers $ n $ problems to the participants. For each problem we know, which friend is sure about the solution. Help the friends find the number of problems for which they will write a solution.

The first input line contains a single integer $ n $ ( $ 1<=n<=1000 $ ) — the number of problems in the contest. Then $ n $ lines contain three integers each, each integer is either $ 0 $ or $ 1 $ . If the first number in the line equals $ 1 $ , then Petya is sure about the problem's solution, otherwise he isn't sure. The second number shows Vasya's view on the solution, the third number shows Tonya's view. The numbers on the lines are separated by spaces.

Print a single integer — the number of problems the friends will implement on the contest.

3
1 1 0
1 1 1
1 0 0

2

2
1 0 0
0 1 1

1

In the first sample Petya and Vasya are sure that they know how to solve the first problem and all three of them know how to solve the second problem. That means that they will write solutions for these problems. Only Petya is sure about the solution for the third problem, but that isn't enough, so the friends won't take it. In the second sample the friends will only implement the second problem, as Vasya and Tonya are sure about the solution.