Family – Count Descendants

The program must accept the first and last names of N persons in a family. The last name of each person indicates the name of his/her father. The program must print the number
of persons(descendants) belonging to the given person’s family.

Boundary Condition(s):
1 <= N <= 50
2 <= Length of each name <= 20

Input Format:
The first line contains N.
The next N lines contain the first and last names of N persons in a family.
The N+2nd line contains a person name.

Output Format:
The first line contains the number of persons(descendants) belonging to the given person’s family.

Example Input/Output 1:
Input:
6
Arun Babloo
Gavin Babloo
Rajesh Arun
Hector Arun
Oliver Hector
Kavin Gavin
Arun

Output:
4

Explanation:
Arun is the father of both Rajesh and Hector.
Hector is the father of Oliver.
So there are 4 persons in the Arun’s family.

Example Input/Output 2:
Input:
12
Catherine John
Rajesh Babloo
Pravin Babloo
Kavin Pravin
Deepa Rajesh
Hector John
Bhuvana Pravin
Arun Kavin
Anu Deepa
Anita Kavin
Jhanvi Bhuvana
Mambo Hector
Pravin

Output:
6

n=int(input())
l=[input().strip().split() for i in range(n)]
s=input().strip()
l1=[s];fi=[]
while(1):
    l2=[];f=0
    for i in l1:
        for j in l:
            if i==j[-1]:
                l2.append(j[0])
                fi.append(j[0])
                f=1
    l1=l2[::]
    if f==0:break
print(len(fi)+1)