#include <iostream>
using namespace std;

int main() {
    char text;
    int countLetter = 0, flag = 1;
    while (flag == 0) {
        cin >> text;
        if ((text >= 'a' && text <= 'z') || (text >= 'A' && text <= 'Z')) {
            ++countLetter;
        } else {
            flag = 0;
        }
        if (flag == 0) {
            break;
        }
    }
    cout << countLetter;
    return 0;
}