PROGRAMMING:Count the letter frequency of English paragraphs

The application of the examination string. Write a function to count the frequency of 26 letters in an English paragraph (26 letters are not case sensitive, frequency refers to the number of times), to input an English English paragraph in the main program, and then to call the function to calculate the frequency of 26 letters, and to output 26 letters in the main function.
###Input format:
Enter in an English paragraph (enter to end paragraph).
###Output format:
Output 26 lines:
Frequency of a -- Z
###Input example:
Here is a set of inputs. For example:
```in
ABCDEFGHIJKLMNOPQRSTUVWXYZ now you see, I can say my ABC. abcdefghijklmnopqrstuvwxyz
```
###Output example:
The corresponding output is given here. For example:
```out
'A' or 'a' :5
'B' or 'b' :3
'C' or 'c' :4
'D' or 'd' :2
'E' or 'e' :4
'F' or 'f' :2
'G' or 'g' :2
'H' or 'h' :2
'I' or 'i' :3
'J' or 'j' :2
'K' or 'k' :2
'L' or 'l' :2
'M' or 'm' :3
'N' or 'n' :4
'O' or 'o' :4
'P' or 'p' :2
'Q' or 'q' :2
'R' or 'r' :2
'S' or 's' :4
'T' or 't' :2
'U' or 'u' :3
'V' or 'v' :2
'W' or 'w' :3
'X' or 'x' :2
'Y' or 'y' :5
'Z' or 'z' :2
```







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