#include <stdio.h>
int main(void){
  int e1,e2,e3,e4;
  scanf("%d %d %d %d",&e1,&e2,&e3,&e4);
    if(e1==e2&&e3==e4){
      printf("yes");
    }else if(e1==e4&&e2==e3){
      printf("yes");
    }else if(e1==e3&&e2==e4){
      printf("yes");
    }else if(e1==e2==e3==e4){
      printf("yes");
    }else{
      printf("no");
    }
    printf("\n");
    return 0;
}
      

