I know you can do this for a string:

```
print("You have inputted {0} postive numbers and {1} negative numbers".format('3','2'))

```

And this would produce:

```
You have inputted 3 postive numbers and 2 negative numbers

```

But I want to insert a letter in a variable name. For example,

```
number = 4
print(nu{}ber.format("m"))

```

And this should produce `4` Any ideas?