#include<stdio.h>
int main(){
    char s[100];
    int i,count=0,digit=1;
    scanf(s,sizeof(s),stdin);
    for(i=0;s[i];i++){
        if(!isdigit(s[i])&&s[i]!='\n')
           digit=0;
        if(isalpha(s[i]))   
    }
    if (digit)
       printf("Invalid input");
    else
       printf("%d",count);
}