#include <stdio.h>
int test(int n){
while(n >= 4){
//printf("%d\n",n);
if( ( n % 100 == 62) || (n % 10 ==4)){
return 1;
}
n = n/10;
}
return 0;
}
int main() {
int a,b;
while(scanf("%d%d",&a,&b)!=EOF && a != 0 && b != 0 ){
int count=0;
for(int i=a;i<=b;i++){
if(test(i) == 0){
count++;
}
}
printf("%d\n",count);
}
return 0;
}