#include <bits/stdc++.h>   using namespace std;   template <class T>   T abs(T x) {     if (x < 0) return -x;     return x;   }   template <class T>   T sqr(T a) {     return a * a;   }   const double pi = acos(-1.0);   const double eps = 1e-8;   int i, n, cnt;   char s1[110], s2[110];   void fun1() {     if (s1[i + 1] ==  0 ) {       s1[i + 1] =  X ;       cnt++;     } else if (s2[i + 1] ==  0 ) {       s2[i + 1] =  X ;       cnt++;     }   }   void fun2() {     if (s1[i + 1] ==  0  && s2[i + 1] ==  0 ) {       s1[i + 1] =  X ;       s2[i + 1] =  X ;       cnt++;     }   }   int main() {     while (2 == scanf( %s%s , &s1, s2)) {       cnt = 0;       n = strlen(s1);       for (i = 0; i < n - 1; i++) {         if (s1[i] ==  0  && s2[i] ==  0 ) fun1();         if (s1[i] ==  0  || s2[i] ==  0 ) fun2();       }       printf( %d n , cnt);     }     return 0;   }   