At least 1 Vowel - N String Values

#include<stdio.h>
#include <stdlib.h>

int main()
{
    int a;
    scanf("%d",&a);
    char b[100],c=0;
    for(int j=0;j<a;j++)
    {
        scanf("\n%s",b);
        for(int i=0;i<strlen(b);i++)
        {
            b[i]=tolower(b[i]);
            if(b[i]=='a'||b[i]=='e'||b[i]=='i'||b[i]=='o'||b[i]=='u')
            {
                c+=1;
                break;
            }            
        }
    }
    if(c==a)
    printf("yes");
    else
    printf("no");
}