#include<stdio.h>
#include<ctype.h)
int main(){char s[100];int
c=0,i=0;
fgets(S,100,stdin);
if(isdigit(s[0])){printf("Invalid input");
return 0;}
for(;s[i];i++)
if(isalpha(s[i]))
c++
printf("%d",c);
}