Excel 2010 if condition occurs in column

i was not really sure how to call the title, but i think this just about describes it.

I want to make a table in Excel 2010 and it looks something like the following:

Table1:

No. | Name | Hours available | Leftover hours |
1 | John | 40 |   |
2 | Pete | 35 |   |
3 | Jane | 24 |   |

Table2:

No. | Client | Hours needed | Who? |
1 | Client 1 | 4 | John |
2 | Client 2 | 16 | Jane |
3 | Client 3 | 8 | Pete |
4 | Client 4 | 9 | John |

In the column 'leftover hours' in table 1, i want the formula to take place. The formula has to check according to the name of it's row, in table 2 if it occurs there, and if it occurs, take the 'Hours needed'. Then take the 'Hours available' and subtract the 'Hours needed' and output the result in its 'Leftover hours'.

In this example; John should have 27 leftover hours, Pete should have 27 leftover hours and Jane should have 8 leftover hours.

I hope what i try to accomplish is clear and i would really appreciate if someone is willing to help me.