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

void process(){
    char description[max_size];
    
    if(fgets(description,max_size,stdin)==NULL){
        return;
    }
    
    int len=strlen(description);
    
    if(len>0 && description[len-1]=='\n'){
        description[len-1]='\0';
        len--;
    }
    
    if(len==0){
        printf("0\n");
        return;
    }
    
    int isonlynumbers=1;
    
    for(int i=0;i<len;i++){
        if(!isdigit(description[i])){
            isonlynumbers=0;
            break;
        }
    }
    
    if(isonlynumbers){
        printf("Invalid input\n");
    }
    else{
        printf("%d\n",len);
    }
}

int main(){
    process();
    return 0;
}