Symmetric pairs in python

symmetric_pairs.py

```
def symmetric_pairs(d):
    for key in d:
        val = d[key]

        if d[val] == key:
            return(val,key)
    return -1,-1


if __name__ == "__main__":

    n=int(input("Enter the number of elements: \n"))
    d = dict(input().split() for _ in range(n))

    result=symmetric_pairs(d)
    print(result)
```

```
Input:
  5 
1 3 
2 3 
3 1 
4 5
5 4
```
```
Output:
      ('3','1')

  ```