#pragma GCC optimize("Ofast")
#pragma GCC target("avx2")

char*mmap();

main(){
	char*rp=mmap(0l,1l<<28,1,2,0,0ll);
	while(*rp++!=10);
	char*a=rp;
	while(*rp++!=10);
	char*b=rp;

	while(*b){
		if(*a==*b){
			++a;
			++b;
		}else{
			putchar(*a++);
		}
	}
}