func_code_string: #include <bits/stdc++.h>   using namespace std;   const int N = 1e6 + 10, p = 1e9 + 7;   int n, cnt[26], inv[N], fac[N], finv[N];   char a[N], b[N];   inline int solve(char *s) {     int ans = 0, noans = fac[n];     memset(cnt, 0, sizeof cnt);     for (int i = 1; i <= n; ++i) ++cnt[a[i] -  a ];     for (int i = 0; i < 26; ++i) noans = 1ll * noans * finv[cnt[i]] % p;     for (int i = 1; i <= n; ++i) {       int v = s[i] -  a ;       noans = 1ll * noans * inv[n - i + 1] % p;       for (int c = 0; c < v; ++c)         if (cnt[c]) {           noans = 1ll * noans * cnt[c] % p;           ans = (ans + noans) % p;           noans = 1ll * noans * inv[cnt[c]] % p;         }       if (!cnt[v]) return ans;       noans = 1ll * noans * cnt[v] % p;       --cnt[v];     }     return ans;   }   int main() {     scanf( %s%s , a + 1, b + 1);     n = strlen(a + 1);     fac[0] = 1;     for (int i = 1; i <= n; ++i) fac[i] = 1ll * fac[i - 1] * i % p;     inv[0] = inv[1] = 1;     for (int i = 2; i <= n; ++i) inv[i] = 1ll * inv[p % i] * (p - p / i) % p;     finv[0] = 1;     for (int i = 1; i <= n; ++i) finv[i] = 1ll * inv[i] * finv[i - 1] % p;     printf( %d , (solve(b) - solve(a) - 1 + p) % p);     return 0;   }   