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

int main(){
    char s[100]
    fgets(s,sizeof(s),stdin);
    
    s[strcspn(s,"/n")]=0;
    
    for(int i=0;i<strlen(s);i++){
      if(!salpha(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;
}