100 atcoder#ABC092B. [ABC092B] Chocolate
[ABC092B] Chocolate
Score : points
Problem Statement
Some number of chocolate pieces were prepared for a training camp. The camp had participants and lasted for days. The -th participant () ate one chocolate piece on each of the following days in the camp: the -st day, the -th day, the -th day, and so on. As a result, there were chocolate pieces remaining at the end of the camp. During the camp, nobody except the participants ate chocolate pieces.
Find the number of chocolate pieces prepared at the beginning of the camp.
Constraints
- ()
- All input values are integers.
Input
Input is given from Standard Input in the following format:
Output
Find the number of chocolate pieces prepared at the beginning of the camp.
3
7 1
2
5
10
8
The camp has participants and lasts for days. Each participant eats chocolate pieces as follows:
- The first participant eats one chocolate piece on Day , , and , for a total of four.
- The second participant eats one chocolate piece on Day and , for a total of two.
- The third participant eats one chocolate piece only on Day , for a total of one.
Since the number of pieces remaining at the end of the camp is one, the number of pieces prepared at the beginning of the camp is .
2
8 20
1
10
29
5
30 44
26
18
81
18
6
56