Problem description.
Ram over slept and is late for class!
Ram doesn’t like to goto college, so he decides
to give his card to his friend. Unfortunately, Teacher got to know that number of students are less then present in the class.
Help Teacher! finding number of proxies.
 

Input
Input description.
First line of input contains N, number of attendance.
The next line contains a string of length N. If the i'th character is '#' means student is present in class or '.' if its a proxy.


Output
Output description.
Print Total number of proxies.

Example
Input:
5
.###.

Output:
2
 

Explanation
In this case N=5The next line contains two('.') and three('#').
So output is two.
n=int(raw_input())
x=raw_input()
count=0
for i in x:
    if i=='.':
        count+=1
print count