#include"stdio.h"
#include"string.h"
long nr_cuvinte,nr_caractere;
int ch(char a)
{
    if((a>='a'&&a<='z')||(a>='A'&&a<='Z'))return 1;
    return 0;
}
int main()
{
FILE *f;f=freopen("text.in","r",stdin);
freopen("text.out","w",stdout);
char temp[10000];int v[10000];int ncv,nch;
while(!feof(f))
{ncv=0;nch=0;
scanf("%s",&temp);
for(int g=0;g<=strlen(temp);g++)v[g]=ch(temp[g]);
for(int g=0;g<=strlen(temp);g++){if((!g||!v[g-1]) && v[g])ncv++;nch+=v[g];}
nr_cuvinte+=ncv;nr_caractere+=nch;}
nr_cuvinte-=ncv;nr_caractere-=nch;
printf("%ld",nr_caractere/nr_cuvinte);
return 0;
}