# Python program to count the number of trailing zeros in Factorial of number N

In this Python program, we will figure out how to include a number of trailing zeros in factorial of N?

### Formula:

``````Trailing 0s in N! = Count of 5s in prime factors of n!
= floor(n/5) + floor(n/25) + floor(n/125) + ....``````

### Example:

``````    Input: N = 23
Output: 4
Factorial of 23 is 25852016738884976640000 which has four trailing 0.

Input: N = 25
Output: 6
Factorial of 25 is 15511210043330985984000000 which has six trailing 0.``````

### Code:

``````# Define a function for finding
# number of trailing zeros in N!
def find_trailing_zeros(num) :
sum = 0
i = 1

# iterating untill quotient is not zero
while(True) :

# take integer divison
quotient = num // (5 ** i)

if(quotient == 0) :
break

sum += quotient
i += 1

return(sum)

# Driver code
if __name__ == "__main__" :

# assigning a number
num = 10

# function call
print("Number of trailing zeros in factorial of",num,"is :",find_trailing_zeros(num))

num = 20

print("Number of trailing zeros in factorial of",num,"is :",find_trailing_zeros(num))
``````

### Output:

``````Number of trailing zeros in factorial of 10 is : 2
Number of trailing zeros in factorial of 20 is : 4``````
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