#include<stdio.h>
#include<string.h>
#include<ctype.h>
int main(){
    char s[100];
    int valid=1;
    fgets(s, sizeof(s), stdin);
    s[strcspn(s,"/n")]="/0";
    for (int i=0;s[i]!='/0';i++){
        if(!isalpha(s[i])&&s[i]!=' '){
            valid=0;
            break;
        }
    }
    if(!valid){
        printf("Invalid input");
        return 0;
    }
    int len=strlen(s);
    int count=0,i=len-1;
    while(i>=0&&s[i]==' ')
    i--;
    while(i>=0&&s[i]!=' '){
        count++;
        i--;
    }
    printf("%d",count);
    return 0;
}