String Modification

The program must accept a string S as the input. The program must remove all the vowels and insert a character “.” before each consonant in the given string S. Then the program must print the modified string as the output.

Note: All the alphabets in S are only in lowercase.

Boundary Condition(s): 3 <= Length of S <=100

Input Format: The first line contains the string S.
Output Format: The first line contains the modified string.

Example Input/Output 1: 
Input:
hello
Output:
.h.l.l

Example Input/Output 2: 

Input:
skillrack
Output:
.s.k.l.l.r.c.k

#include <stdio.h>
#include<string.h>
int main()
{
    char str[101],st[101];
    scanf("%s",str);
    int i,cnt=0,l=strlen(str);
    for(i=0;i<l;i++)
        if(str[i]!='a' && str[i]!='e' && str[i]!='i' && str[i]!='o' &&str[i]!='u')
        {
            st[cnt++]='.';
            st[cnt++]=str[i];
        }
    printf("%s",st);
    return 0;
}