title: Sum of values in Python, excluding equal values
body: <p>Return the sum of 3 numbers, but if they're the same, they dont count towards the total. Can you help me find what's wrong in my code please?</p>
  
  <pre><code>def lone_sum(a,b,c):
      t=0
      if a==b and a!=c:
          t=a+c
      elif a==c and a!=b:
          t=a+b
      elif b==a and b!=c:
          t=b+c
      elif b==c and b!=a:
          t=b+a
      elif c==a and c!=b:
          t=a+b
      elif c==b and c!=a:
          t=b+a
      elif a==b and b==c:
          t=a
      return t
  </code></pre>