DSA problem "multipleof3" soloution please tell why it is not pass all the test case

#include
using namespace std;

int main() {
// your code goes here
long long int n;
cin>>n;
long long int i=0,j=0;
cin>>i>>j;
i=i10+j;
long long int m=0;
for(long long int k=0;k<n-2;k++)
{ long long int z=i;
long long int d=0;
m=0;
while(z)
{
d=z%10;
z=z/10;
m=m+d;
}
i=i
10+(m%10);
}
if(i%3==0)
cout<<“YES”<<endl;
else
cout<<“NO”<<endl;

}