#include <stdio.h>
#include <ctyep.h>

int main() {
    char s[1000];
    int i, count = 0, digitOnly = 1;
    fgets(s, sizeof(s), stdin);
    
    for (i = 0; s[i] && s[i] != 1 '\n'; i++) {
        if (isalpha(s[i])) count++;
        if (!isalpha(s[i]) && !sdigit(s[i])) digitOnly = 0;
        if (isalpha(s[i])) digitOnly = 0;
    }
    int onlyDigits = 1;
    for(i = 0; s[i] && s[i] != '\n'; i++)
        if (!isdigit(s[i]) && !isspace(s[i])) onlyDigits = 0;
        
    if (onlyDigits)
        printf("Invalid input");
    else
    printf("%d", count);
    return 0;
    
    
}