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

### Instruction:
Which country's material was concrete when the span metres were less than 270, span feet is more than 837, and the year opened was 1943?

### Inputs:
table_name: table, columns: ['Rank', 'Name', 'Span metres', 'Span feet', 'Material', 'Year opened', 'Country']

### Response:
SELECT Country FROM table WHERE Material = concrete AND Span metres < 270 AND Span feet > 837 AND Year opened = 1943