#include<cstdio>
#include<string.h>
int nc,nr,nn,n2,i;
char s[100010];
int main()
{
	freopen("text.in","r",stdin);
	freopen("text.out","w",stdout);
	nc=nr=0;
	while(scanf("%s",&s)!=EOF)
	{
		nn=n2=strlen(s);
		for(i=0;i<nn;i++)
			if(!(('a'<=s[nn-1]&&s[nn-1]<='z')||('0'<=s[nn-1]&&s[nn-1]<='9')))
				n2--;
		nr=nr+n2;
		if(n2>=0)
			nc++;
	}
	printf("%d",nr/nc);
	return 0;
}