#include <assert.h>
int unknown1();
int unknown2();
int unknown3();
int unknown4();

int main() {


	int w = 1;
	int z = 0;
	int x= 0;
	int y=0;


         while(unknown2()){
	    if(w) {
		x++;
		w=!w;
	    };
	    if(!z) {
		y++;
		z=!z;
	    };
	}

         if (!(x==y)) return 42;
 UFO: goto UFO;
         //static_assert(x==y);

}
