João has, in his garden, a cistern where he stores rainwater and takes water to water his flowers. At midnight on December 31, 2005, the cistern contained 156 liters of water. João has the habit of writing on a board, every day, the number of liters of water he spends to water the flowers and the amount of rainwater collected.

Below we see part of the board referring to the first 8 days of January 2006. How many liters of water were in João's cistern at midnight on January 8, 2006?

| Jan | flowers(l) | rain(l) |
| :---: | :---: | :---: |
| 1 | 6 | 2.5 |
| 2 | 9 | 0 |
| 3 | 0 | 5 |
| 4 | 4 | 0 |
| 5 | 9 | 3 |
| 6 | 0 | 0 |
| 7 | 11 | 4.5 |
| 8 | 0 | 0 |
On January 1st, the cistern starts with 156 liters of water, and from then on, the cistern receives rainwater and loses water for watering flowers. Since there was no change in the amount of water in the cistern on the 8th, the number of liters of water in the cistern on the 8th is

$156+$ rainwater from day 1 to day 7 - water for watering from day 1 to day 7.

The statement says that the second term of the expression above is the sum of the numbers in the third column, which is $2.5+0+5+0+3+0+4.5=15$ and the third term is the sum of the numbers in the second column of the table, which is $6+9+0+4+9+0+11=39$. Therefore, the number of liters of water in the cistern, at midnight on the 8th, is $156+15-39=132$.