#include<stdio.h>
#include<string.h>
#include<ctype.h>
int main(){
    char s[101];
    fgets(s,sizeof(s),stdin);
    s[strcspn(s, "\n")]="\0";
    int len=strlen(s);
    for(int i=0;i<len;i++){
        if(!(isalpha(s[i])|| isspace(s[i]))){
            printf("invalid input\n");
            return 0;
        }
    }
    int end=len-1;
    while(end>=0&&isspace(s[end])){
        end--;
    }
    int l=0;
    while(end>=0&&isalpha(s[end])){
        l++;
        end--;
    }
    printf("%d\n",l);
    return 0;
}