PBc

#include <iostream>
#include <math.h>
using namespace std;


int main(){

  int a,b,c,ca,cc,i=0,Sc,Sa;

  cin>>a>>b;
  c=b;
  while (a!=0&&b!=0)
  {
      cin>>c;
       if (c==0)
        break;
     // ca=a;
      cc=c;
      Sa=0;
      Sc=0;
      while (a!=0)
      {
          Sa+=a%10;
          a/=10;
      }

      while (c!=0)
      {
          Sc+=c%10;
          c/=10;
      }

      if ((Sa+Sc)==b)
      {
          i++;
          // cout<<ca<<" "<<b<<" "<<cc;
      }
      a=b;
      b=cc;

  }
    cout<<i;

   return 0;
}