#include<stdio.h>
#include<ctype.h>
int main() {
    char str[200];
    int i, count=0;
    int haas_alpha =0;
    fgets(str, sizeof(str), stdin);
    for (i=0; str[i] != '\0'; i++) {
        if (isalpha(str[i])) {
            count++;
            has_alpha = 1;
        }
        else if (str[i] == ' ' || str[i] == '\n') {
            continue;
        }
    }
    if(has_alpha == 0) {
        printf("Invalid input");
    }
    else {
        printf("%d", count);
    }
    return 0;
}