题目描述
Elevator hall number
JAG (Japanese Alumni Group) is a mysterious organization headquartered in a skyscraper somewhere in Tokyo. There are $ N $ elevators in operation in this building, and the $ i $ elevators stop on each floor from the $ low_i $ floor to the $ high_i $ floor ($1 \ le i \ le N$).
Mr. X, a new staff member of JAG, arrived at the elevator hall of the building to visit the headquarters. Mr. X, who pressed a button and waited for the elevator, noticed that the display on the floor where the elevator is currently located has changed slightly. When the $ i $ elevator is on the $ a_i $ floor, arrange $a_1, a_2, \ ldots, a_N$ in this order, and connect them in decimal notation with no leading 0 and no spaces. The one number you write is shown on the display. For example, if $ N = 3 $ and the elevators are on the $ 10 $ floor, the $ 2 $ floor, and the $ 11 $ floor in that order, $ 10211 $ will be displayed.
Mr. X was wondering how many numbers could be shown on the display. Your task is to create a program that seeks it.
Input
The input consists of multiple datasets, each of which has the form:
$ N $
$ low_1 $ $ high_1 $
...
$ low_N $ $ high_N $
The first row of the dataset consists of the integer $ N $ ($2 \ le N \ le 6$) representing the number of elevators. Of the following $ N $ lines, the $ i $ line consists of $ 2 $ integers $ low_i $, $ high_i $ ($1 \ le low_i \ le high_i \ le 99$), and the $ i $ elevator is Represents the range of movement.
The end of the input is represented by a line containing only $ 1 $ of zeros.
Output
For each dataset, print the number of possible displays in $ 1 $ lines.
Sample Input
2
1 11
1 11
3
10 10
twenty two
11 11
Four
89 91
1 12
1 12
89 91
Five
1 8
2 76
10 19
6 16
33 42
6
10 59
20 69
30 79
40 89
50 99
50 99
0
Output for Sample Input
120
1
1278
659520
15625000000
Example
Input
2
1 11
1 11
3
10 10
2 2
11 11
4
89 91
1 12
1 12
89 91
5
1 8
2 76
10 19
6 16
33 42
6
10 59
20 69
30 79
40 89
50 99
50 99
0
Output
120
1
1278
659520
15625000000
输入格式
见题面
输出格式
见题面