An array called nums has already been created for you with the values {10, 20, 30, 40, 50}.

Your task is to add up only the elements that are at even index positions (indices 0, 2, and 4) and print the sum.

This is different from summing even numbers: here you are checking whether the index is even, not the value. The elements at even indices are:
- Index 0: 10
- Index 2: 30
- Index 4: 50

Their sum is 90.

Print the result in this exact format:
Sum at even indices: 90