#include <stdio.h>
int main(void){
    int a=0,b=0,c=0;
    scanf("%d %d",&a,&b);
    c=b-1;
    if(a<=c){
        printf("YES\n");
        printf("0");
    }else{
        printf("NO\n%d",a-c);
    }
    return 0;
}