There are n cities and m roads, each road is **unidirectional**. Sinzo wants to build some roads, to make each city can reach other cities. Please tell how many roads should Sinzo construct at least?

Submit: 909 Solved: 198

[Submit][Status][Web Board]

**unidirectional**

**unidirectional**

Please output the number of roads to construct in one line.

```
4 4
1 2
2 3
3 1
3 4
```

`1`