First X Consonants

The program must accept a string S and an integer X as the input. The program must print the first X consonants in the string S as the output. If the number of consonants in the string S is less than X then the program must print -1 as the output.
Note: The string S contains only alphabets.

Boundary Condition(s):
1 <= Length of S <= 100
1 <= X <= Length of S

Input Format:
The first line contains the string S.
The second line contains the value of X.

Output Format:
The first line contains either the first X consonants in S or -1.

Example Input/Output 1:
Input:
SkillRack
5

Output:
SkllR

Explanation:
The first 5 consonants in the string "SkillRack" are S, k, l, l and R.
So they are printed as the output.

Example Input/Output 2:
Input:
Dengue
6

Output:
-1

Solution :-

#include<stdio.h>

#include <stdlib.h>

int isvowel(char ch)

{

    ch=tolower(ch);

    

    if(ch=='a'||ch=='e'||ch=='i'||ch=='o'||ch=='u')

    {

        return 1;

    }

    

    return 0;

}

int main()

{

    char str[100];

    int x,z=0;

    

    scanf("%s\n%d",str,&x);

    

    int len=strlen(str);

    char arr[len];

    

    for(int i=0;i<len;i++)

    {

        if(!isvowel(str[i]))

        {

            arr[z]=str[i];

            z++;

        }

        

    }

    

    if(z<x)

    printf("-1");

    else

    {

        for(int i=0;i<x;i++)

        {

            printf("%c",arr[i]);

        }

    }

}