PROGRAMMING:Count the number of 0 at the end
Given two positive integers a and B (a < b), count how many zeros are at the end of the product of all integers from a to B. For example, given that the two numbers are 10 and 20, the formula to be calculated is:
ten × eleven × twelve × thirteen × fourteen × fifteen × sixteen × seventeen × eighteen × nineteen × twenty
The result of this formula is 6704425728000 with three zeros at the end.
The result of this formula is too big. Maybe you can find a simple algorithm. You don't need to calculate the result of the whole formula to know the number of zeros at the end of it!
####Input format
```
Two integers a and B (a < B and no more than 100000) separated by several groups of spaces, one line for each group.
```
####Output format
Each group of input data corresponding to the output of an integer, occupies a single line, is the number of 0 at the end of the result of multiplying from a to B.
###Input sample
```in
1 10
125 128
1 100
21 24
```
####Output sample
```out
two
three
twenty-four
0
```
answer：If there is no answer, please comment
ten × eleven × twelve × thirteen × fourteen × fifteen × sixteen × seventeen × eighteen × nineteen × twenty
The result of this formula is 6704425728000 with three zeros at the end.
The result of this formula is too big. Maybe you can find a simple algorithm. You don't need to calculate the result of the whole formula to know the number of zeros at the end of it!
####Input format
```
Two integers a and B (a < B and no more than 100000) separated by several groups of spaces, one line for each group.
```
####Output format
Each group of input data corresponding to the output of an integer, occupies a single line, is the number of 0 at the end of the result of multiplying from a to B.
###Input sample
```in
1 10
125 128
1 100
21 24
```
####Output sample
```out
two
three
twenty-four
0
```
answer：If there is no answer, please comment