This if statement seems okay to me, but I get a syntax error. What am I missing?

Everything seems right in this bit of code -- syntax, indentation, etc. But I get a syntax error on the last "else" when I try to run it.

    if m.startswith('R') :
        if i>6 :
            checklistPRE = markers[i-6:i+6]
            idxS = []
            for j in range(0,12) :
                if checklistPRE[j].startswith('S') :
                    idxS.append(j)
                else :
                    pass
            checklist = checklistPRE[min(idxS):max(idxS)
        else :
            checklist = markers[0:i+6]
        markercount = checklist.count(m)

So, what's wrong with that last else statement? It's in line with the second if statement on line 2; can't see what's wrong here.

Thanks for the help guys.