#include<stdio.h>
#include<string.h>
#include<ctype.h>
int main(){
    char str[101];
    int isDigitOnly=1;
    fgets(str ,sizeof(str) , stdin);
    str[strcspn(str,"\n")]='\0';
    for(int i=0;str[i!='\0';i++){
        if(isdigit((unsigned char)str[i])){
            isDigitOnly=0;
            break;
        }
    }
    if(isDigitOnly)
        printf("Invalid input");
        else
        printf("%lu",strlen(str));
        
        return 0;
}