#include <stdio.h>
#include <stdlib.h>

int main()
{
int stat;
int a,b;


 printf("GCD calcs \n");
 printf("enter two numbers, type -1 -1 \n");
 for(;;)
 {
 fflush(stdin);
 stat= scanf("%d %d",&a,&b);

 while(stat != 2)
   {
   fflush(stdin);
   printf("error in input try again\n");
   stat= scanf("%d%d",&a,&b);
   }

 if(a== -1)
   exit(1);
 else
  {
   printf("GCD of %d ,%d  IS  %d \n",a,b,GCD(a,b));
  }
}
}