Sum the request durations between spans using Trace QL

Trying to get the sum of durations between the spans.

The following query tried “{name=“Span1”} >> {name=“Span10”} | sum(duration)”.

Error (invalid TraceQL query: parse error at line 1, col 109: syntax error: unexpected $end).

I am using grafana cloud trial account for traces and creating dashboard based on my requirements.

Any recommendations?