#include #include #include int gcd(int a, int b) { while (a != 0) { int c = a; a = b%a; b = c; } return (b<0) ? -b : +b; } #define MAX 15000000 int rad[MAX]; // A007947, 0 means already used bool isprime[MAX]; int unseen = 1; #define K 3 int rrr[K]; int other() { int forbidden = rrr[0]; for (int k=1; k