#include <stdio.h>
int main(){
	int a[1000000]; int x, i;
	while (x!=-1) {
		scanf("%d", &x);
		a[x]=1;
	}
	while (x!=-1) {
		scanf("%d", &x);
		if (a[x]==1);
		a[x]=a[x]+1;
	}
	for (; i<1000000; i++){
		if (a[i]=2)
		printf("%d", i);
	}
return 0;
}