Implement the [Polybius square cipher](http://en.wikipedia.org/wiki/Polybius_square).
Replace every letter with a two digit number. The first digit is the row number, and the second digit is the column number of following square. Letters `'I'` and `'J'` are both 24 in this cipher:
table#polybius-square {width: 100px;}
table#polybius-square td {background-color: #2f2f2f;}
table#polybius-square th {background-color: #3f3f3f;}
12345
1ABCDE
2FGHI/JK
3LMNOP
4QRSTU
5VWXYZ
Input will be valid (only spaces and uppercase letters from A to Z), so no need to validate them.
## Examples
```python
polybius('A')  # "11"
polybius('IJ') # "2424"
polybius('CODEWARS') # "1334141552114243"
polybius('POLYBIUS SQUARE CIPHER') # "3534315412244543 434145114215 132435231542"
```
def polybius(text):
    numeric_key = {"a": "11", "b": "12", "c": "13", "d": "14", "e": "15",
            "f": "21", "g": "22", "h": "23", "i": "24", "j": "24", "k": "25",
            "l": "31", "m": "32", "n": "33", "o": "34", "p": "35",
            "q": "41", "r": "42", "s": "43", "t": "44", "u": "45",
            "v": "51", "w": "52", "x": "53", "y": "54", "z": "55",
            " ": " "
        }
    numeric_string = ""
    for character in text.lower():
        numeric_string += numeric_key[character]
    return numeric_string
def polybius(text):
    numeric_key = {"a": "11", "b": "12", "c": "13", "d": "14", "e": "15",
            "f": "21", "g": "22", "h": "23", "i": "24", "j": "24", "k": "25",
            "l": "31", "m": "32", "n": "33", "o": "34", "p": "35",
            "q": "41", "r": "42", "s": "43", "t": "44", "u": "45",
            "v": "51", "w": "52", "x": "53", "y": "54", "z": "55",
            " ": " "
        }
    numeric_string = ""
    for character in text.lower():
        numeric_string += numeric_key[character]
    return numeric_string