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

int main() {
    char s[25];
    fgets(s, sizeof(s), stdin);
    
    s[strcspn(s, "\n")] = 0;
    
    for(int i = 0; s[i] != '\0';i++) {
        if(!isalpha(s[i]) && !isspace(s[i])) {
            printf("Invalid\n");
            return 0;
        }
    }
    int len = strlen(s);
    int count = 0;
    
    int i = len-1;
    while(i>=0 && s[i] == '')
    i--;
    
    while(i>=0 && s[i] != ''){
        count++;
        i--;
    }
    printf("%d\n", count);
    return 0;
    
}