#include <fstream>
using namespace std;
ifstream in("text.in");
ofstream out("text.out");
int cuv,lit;
string s;
bool check(char c)
{
    return (c>='a'&&c<='z')||(c>='A'&&c<='Z');
}
void solve(int l,int r)
{
    if(l>r)
        return;
    if(!check(s[l]))
        return solve(l+1,r);
    cuv++;
    lit+=r-l+1;
    for(;l<=r;l++)
        if(!check(s[l]))
        {
            lit-=r-l+1;
            return solve(l+1,r);
        }
}
int main()
{
    while(in>>s)
        solve(0,s.size());
    out<<lit/cuv;
    return 0;
}