func_code_string: #include <bits/stdc++.h>   using namespace std;   const long long INF = 1e17;   const long long maxn = 2e5 + 700;   const int mod = 1e9 + 7;   template <typename T>   inline void read(T &a) {     char c = getchar();     T x = 0, f = 1;     while (!isdigit(c)) {       if (c ==  - ) f = -1;       c = getchar();     }     while (isdigit(c)) {       x = (x << 1) + (x << 3) + c -  0 ;       c = getchar();     }     a = f * x;   }   long long n, m, p;   char s[maxn];   int a[maxn], b[maxn];   int digit(long long x, int *d) {     int ans = 0;     while (x) {       d[++ans] = x % 10;       x /= 10;     }     return ans;   }   int path[maxn];   int check(int pos, int lbound, int rbound) {     if (!pos) return 1;     if (!lbound && !rbound) return 1;     int l = lbound ? a[pos] : 0;     int r = rbound ? b[pos] : 9;     for (int i = l; i <= r; i++) {       if (path[i] > 0) {         path[i]--;         if (check(pos - 1, lbound && i == l, rbound && i == r)) {           path[i]++;           return 1;         }         path[i]++;       }     }     return 0;   }   int pos, res = 0;   void dfs(int u, int w) {     if (u == 9) {       path[u] = w;       if (check(pos, 1, 1)) res++;       return;     }     for (int i = 0; i <= w; i++) {       path[u] = i;       dfs(u + 1, w - i);     }   }   int main() {     read(n);     read(m);     digit(n, a);     pos = digit(m, b);     dfs(0, pos);     printf( %d n , res);     return 0;   }   