思路：
数位的一道入门题

，表示第位，第是否是的结果。

Code：

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int maxn = 1e3+7;
inline ll read() {
    ll s = 0, w = 1;
    char ch = getchar();
    while (ch < 48 || ch > 57) {
        if (ch == '-') w = -1;
        ch = getchar();
    }
    while (ch >= 48 && ch <= 57)
        s = (s << 1) + (s << 3) + (ch ^ 48), ch = getchar();
    return s * w;
}
ll dp[10][2];
int digit[10];
ll dfs(int len,int p1,bool limit) {
    if(!len) return 1;
    if(!limit&&dp[len][p1==6]!=-1) return dp[len][p1==6];
    int endi=(limit?digit[len]:9);
    ll ans=0;
    for(int i=0;i<=endi;++i) {
        if(i==4||p1==6&&i==2) continue;
        ans+=dfs(len-1,i,limit&&i==endi);
    }
    if(!limit) dp[len][p1==6]=ans;
    return ans;
}
ll solve(int n) {
    int len=0;
    while(n) {
        digit[++len]=n%10;
        n/=10;
    }
    return dfs(len,0,true);
}
int main() {
    int n,m;
    memset(dp,-1,sizeof dp);
    while(~scanf("%d%d",&n,&m)) {
        if(n==0&&m==0) return 0;
        printf("%lld\n",solve(m)-solve(n-1));
    }
    return 0;
}