include

include

using namespace std;

int main()
{
vector<char> vec;
char tem;
while(tem = getchar())
{
if(tem == '\n')
break;
vec.push_back(tem);
}
for(int i = 0;i<vec.size();i++)
{
for(int j = i+1;j<vec.size();j++)
{
if(vec[i] == vec[j])
{
vec.erase(vec.begin()+j);
j = j-1;
}
}
}
cout<<vec.size();</char>

}