Friend requests in social network

In a social network, a person can invite friends of his/her friend. John wants to invite and add new friends. Complete the program below so that it prints the names of the persons to whom John can send a friend request.

Input Format: The first line contains the value of the N which represent the number of friends. Next N lines contain the name of the friend F followed by the number of friends of F and finally their names separated by space. 

Boundary Conditions: 2 <= N <= 10 

Output Format: The names to which John can send a friend request. 

Example Input/Output 1: 

Input: 

3 

Mani 3 Ram Raj Guna 

Ram 2 Kumar Kishore 

Mughil 3 Praveen Naveen Ramesh 

Output: 

Raj Guna Kumar Kishore Praveen Naveen Ramesh 

Explanation: Ram is not present in the output as Ram is already John's friend. 

Example Input/Output 2: 

Input: 

4 

Arjun 3 Bhuvana Ramya Rajesh 

Naveen 2 Arjun Sangeetha 

Rajesh 3 Narmada Madan Suresh 

Suresh 2 Pawan Adhil

Output: 

Bhuvana Ramya Sangeetha Narmada Madan Pawan Adhil

Source Code:

#include<stdio.h> 

int main()

{

int n,t,i,j=0,k,f;

char a[100][100],b[100][100];

scanf("%d",&n);

for(i=0;i<n;i++)

{

    scanf("%s %d",a[i],&t);

    while(t--)

        scanf("%s",b[j++]);

}

for(i=0;i<j;i++)

{

    f=0;

    for(k=0;k<n;k++)

    {

        if(strcmp(a[k],b[i])==0)

            f=1;

    }

    if(f==0)

        printf("%s ",b[i]);

}

}