#include
#include
#include
#include
#include
#include
using namespace std;
int main()
{
string a,b,c;
cin >> a >> b >> c;
int len = a.length();
int res = 0;
for (int i = 0; i < len; ++i) {
set<int>s;
s.insert(a[i]);
s.insert(b[i]);
s.insert(c[i]);
if (s.size() == 2) ++res;
if (s.size() == 3) res += 2;
}
cout << res << endl;
return 0;