#include <stdio.h>
#include <string.h>
#include <ctype.h>

int main() {
    char s[21];
    fgets(s, sizeof(s),stdin);
    s[strcspn(s, "\n")] = 0;
    
    for (char*p = s; *p; p++)
    if(!isalpha(*p) && *p != '') {
        printf("Invalid input/n");
        return 0;
    }
    char*last = strrchr(s,'');
    int len = last ? strlen(last + 1): strlen(s);
    printf("%d/n", len);
    return 0;
}