C++

C++
#include<iostream>
using namespace std;
int main()
{
char s;
int num=0;
int x[128]={0};
while(cin>>s)
{
if(int(s)>=0&&int(s)<=127&&x[int(s)]==0)
{
num++;
x[int(s)]=1;
}
}
cout<<num;
}</iostream>