ソースコード
#define _USE_MATH_DEFINES
#include <iostream>
#include <iomanip>
#include <math.h>
#include <climits>
#include <algorithm>
#include <functional>
#include <vector>
#include <queue>
#include <map>
#include <set>
#include <string>
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<ll, ll> P;
const ll MD = 1000000007;
/* sample input
*/
int main()
{
string s;
cin >> s;
int len = s.length();
int alpha[26] = {};
int answer = 0;
for (int i = 0; i < len; i++) {
for (int j = 0; j < 26; j++) {
if (s[i] == 'a' + j) {
alpha[j]++;
}
}
}
for (int i = 0; i < 26; i++) {
if (alpha[i] > 0) {
answer++;
}
}
cout << answer;
return 0;
}