//prime number generator
#include <stdio.h>
#include <math.h>

int main()
{
    int A [50000]={2,3,5,7,11};//the first set of primes excluding 11
    int * B = &A[4];//current prime number
    int * C = &A[0];//first prime number
    int sB;
    while (1){
        if ((*B % *C)==0){
            C=&A[0];
            *B=((*B+2)%10)==5?*B+4:*B+2;
            sB = (int)sqrt((double)*B);
        }
        else if ((*C)>sB){
            B++;
            if (B==&A[50000]){
                B--;
                break;
            }
            *B=((*(B-1)+2)%10)==5?*(B-1)+4:*(B-1)+2;
            sB = (int)sqrt((double)*B);
            C=&A[0];
        }
        C++;
    }
    printf("%i\n",*B);

}