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

int main(){
    char s[21];
    fgets(s, sizeof(s), stdin);
    
    int len = strlen(s);
    if(s[len - 1]== '\n') s[len - 1]== '\0';
    
    for (int i = 0; s[i]!= '\0';i++){
        if(!isalpha(s[i]) && s[i]!='');{
            printf("Invalid input\n");
            return 0;
        }
    }
    char *token = strtok(s," ");
    char *lastWord = token;
    
    while(token != NULL){
        lastWord = token;
        token = strtok(NULL," ");
    }
    printf("%lu\n",strlen(lastWord));
    return 0;
}