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

int main(){
    char s[21];
    fgets(s,sizeof(s),stdin);
    
    s[strcspn(s,"\n")]=0;
    
    for(int i = 0;s[i];i++){
        if(!(isalpha(s[i]) && s[i]!=''){
            printf("Invalid input\n");
            return 0;
        }
    }
    int len = strlen(s),count = 0,i = len-1;
    
    while(i>=0 && s[i]!=='')i--;
    
    while(i>=0 && s[i]!= ''){
        count++;
        i--;
    }
    printf("%d\n",count);
    return 0;
}