Primary Register Solution:

#include <stdio.h>
 
int main(void) {
	int registers[8] = {2 , 3, 5, 7, 11, 13, 17, 19};
	int i1, i2, i3, i4, i5, i6, i7, i8;
	scanf("%d %d %d %d %d %d %d %d", &i1, &i2, &i3, &i4, &i5, &i6, &i7, &i8);
	printf("%d", ((1-i1) + ((2-i2)*registers[0]) + ((4-i3)*registers[1]*registers[0]) + ((6-i4)*registers[2]*registers[1]*registers[0]) + ((10-i5)*registers[3]*registers[2]*registers[1]*registers[0]) + ((12 - i6)*registers[4]*registers[3]*registers[2]*registers[1]*registers[0]) + ((16 - i7)*registers[5]*registers[4]*registers[3]*registers[2]*registers[1]*registers[0]) + ((18 - i8)*registers[6]*registers[5]*registers[4]*registers[3]*registers[2]*registers[1]*registers[0])));
	return 0;
}