#include <stdio.h>
#include <ctype.h>

int main() {
    char c;
printf("Enter a stream of characters:");
    while((c=getchar())!= '\n')
{
    
    if(isalpha(c))
    {
    if((c=='a')||(c=='e')||(c=='i')||(c=='o')||(c=='u')||(c=='A')||(c=='E')||(c=='I')||(c=='O')||(c=='U'))
    putchar(toupper(c));
    else
    putchar(tolower(c));
    }
}

    return 0;
}