// yuki 998
// 2020.2.28 bal4u

#include <stdio.h>

int getchar_unlocked(void);
#define gc() getchar_unlocked()

int in() {  // 整数の入力
	int n = 0; int c = gc();
	do n = 10*n + (c & 0xf), c = gc(); while (c >= '0');
	return n;
}

int a[110];
int main()
{
	int i, j;

	for (i = 0; i < 4; ++i) a[in()]++;
	for (j = 0; a[j] == 0; ++j);
	for (i = 0; i < 4; ++i) {
		if (a[i+j] != 1) break;
	}
	puts(i == 4? "Yes": "No");
	return 0;
}