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

int main(){
    char s[100];
    fgets(s, sizeof(s),stdin);
    
    size_t len = strlen(s);
    if(len > 0 && s[len - 1] == '\n'){
        s[len - 1] = '\0';
        len--;
    }
    
    for (int i = 0; s[i]!=''){
        if(!isalpha(s[i])!= ''){
            printf("invalid input");
            return 0;
            
        }
    }
    int i = len - 1;
    
    while(i >= 0 & & isalpha(s[i])){
        lastWordLength = 0;
        i--;
    }
    
    printf("%d", lastWordLength);
    return 0;
}