#include<stdio.h>
#include<string.h>
int main()
{
	char s[10000];
	int i,g;
	scanf("%s",&s);
	for(i=0;i<strlen(s);i++){
		if(s[i]=='1'||s[i]=='2'||s[i]=='3'||s[i]=='4'||s[i]=='5'||s[i]=='6'||s[i]=='7'||s[i]=='8'||s[i]=='9'){
			g+=s[i]-48;
		}
	}
	printf("%d\n",g-1);
	return 0;
}