Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
What is the smallest height (ft) of a building in Frankfurt with a height (m) of 257 and less than 55 floors?

### Inputs:
table_name: table, columns: ['Name', 'City', 'Height (m)', 'Height (ft)', 'Floors', 'Years as tallest']

### Response:
SELECT MIN Height (ft) FROM table WHERE City = frankfurt AND Height (m) = 257 AND Floors < 55