/* Test n, reverse(n) for primeness. */
#include <stdio.h>
int isPrime(int n);
int reverse(int n);

int main() {
    int	limit, n, r;
    printf("Enter limit: ");
    scanf("%d", &limit);
    for (n = 2; n <= limit; ++n) {
	if (!isPrime(n)) continue;
	r = reverse(n);
	if (!isPrime(r)) continue;
	printf("%d and %d are prime.\n",
	       n, r);
    }
    return 0;
}