/*
 * fourdigit.c - find ten four-digit prime numbers whose base ten
 * representation ends in a '7'.
 *
 * Algorithm: Start with 1001, go up by twos, and find and print ten prime
 * numbers.
 */

#include <stdio.h>

int main()
{
    int i, nleft;
    extern int isprime(int p);

    nleft = 10;
    for (i = 1001; nleft > 0; i = i + 2) {
	if (i % 10 == 7 && isprime(i)) {
	    printf("%d\n", i);
	    nleft = nleft - 1;
	}
    }

    return 0;
}