I graphed it own in my own little way to find that i shook five hands.
Person with 9shakes - shakes hands of all
Person with 8shakes - shakes hands of all except person with 1 shake
Person with 7shakes - shakes hands of all except person with 1 and 2 shakes
Person with 6shakes - shakes hands of all except person with 1,2, and 3 shakes
Person with 5shakes - shakes hands of all except person with 1,2,3 and 4 shakes
Person with 4shakes - shakes hands with person with 9,8,7, and 6 shakes
Person with 3shakes - shakes hands with person with 9,8, and 7 shakes
Person with 2shakes - shakes hands with person with 9 and 8 shakes
person with 1 shake - shakes hands with person with 9 shakes.
if you count the "shakes with all", there are 5, thus meaning person x(me) shook hands with 5 people.
the only people person "x" did NOT shake hands with would be 1,2,3, or 4.
We have been told that "3" is wrong, thus leaving my girlfriend as the one who made 1,2, or 4 shakes. and this is what i found with my crazy mixed lines picture.