#include <stdio.h>

int main(void)
{
    int n[4],i,min=100,max=0,count=0;
    scanf("%d %d %d %d",&n[0],&n[1],&n[2],&n[3]);

    for(i=0;i<=3;i++)
    {
        if(min>=n[i]){
            min=n[i];
        }
        if(max<=n[i]){
            max=n[i];
        }
    }

    if(min+1==n[0] || min+1==n[1] || min+1==n[2] || min+1==n[3]){
        if(min+2==n[0] || min+2==n[1] || min+2==n[2] || min+2==n[3]){
            if(min+3==n[0] || min+3==n[1] || min+3==n[2] || min+3==n[3]){
                printf("Yes");
            }else{
                printf("No");
            }
        }else{
            printf("No");
        }
    }else{
        printf("No");
    }
    return 0;
}