func_code_string: #include <bits/stdc++.h>   using namespace std;   long long gcd(long long a, long long b) { return b == 0 ? a : gcd(b, a % b); }   const int MAXLEN = 15;   long long dp[MAXLEN + 1][2];   long long dpleq[MAXLEN + 1][2];   inline int conv(char c) {     if (isdigit(c)) return c -  0 ;     if (islower(c)) return c -  a  + 10;     assert(false);   }   long long calc(char* s) {     int slen = strlen(s);     long long ret = 0;     for (int mx = (0); mx < (16); ++mx) {       int pos = mx / 4, off = mx % 4;       if (pos >= slen) continue;       memset(dp, 0, sizeof(dp));       memset(dpleq, 0, sizeof(dpleq));       dp[0][0] = dpleq[0][0] = 1;       for (int i = (0); i < (slen); ++i)         for (int j = (0); j < (2); ++j)           for (int k = (0); k <= (mx); ++k) {             if (i == pos && (k & (1 << off)) == 0) continue;             int nj = j == 1 || k == mx ? 1 : 0;             dp[i + 1][nj] += dp[i][j];             if (k < conv(s[i]))               dpleq[i + 1][nj] += dp[i][j];             else if (k == conv(s[i]))               dpleq[i + 1][nj] += dpleq[i][j];           }       long long cur = dpleq[slen][1];       ret += cur;     }     return ret;   }   void dec(char* s) {     for (int i = 0;; ++i)       if (s[i] ==  0 )         s[i] =  f ;       else {         assert(s[i] !=   0 );         if (s[i] ==  a )           s[i] =  9 ;         else           --s[i];         break;       }     int slen = strlen(s);     while (slen >= 2 && s[slen - 1] ==  0 ) --slen;     s[slen] =   0 ;   }   int nq;   char sl[MAXLEN + 1], sr[MAXLEN + 1];   long long solve() {     reverse(sl, sl + strlen(sl));     reverse(sr, sr + strlen(sr));     long long ret = calc(sr);     if (strcmp(sl,  0 ) != 0) {       dec(sl);       ret -= calc(sl);     }     return ret;   }   void run() {     scanf( %d , &nq);     for (int qi = (0); qi < (nq); ++qi) {       scanf( %s%s , sl, sr);       printf( %lld n , solve());     }   }   int main() {     run();     return 0;   }   