#include <bits/stdc++.h>
using namespace std;
ifstream f("text.in");
ofstream g("text.out");
int main()
{   int nrc=0,lgt=0,lgc=0;
    char c;
    while(f.get(c))
    {   if((c>='a' && c<='z') || (c>='A' && c<='Z')) lgc++;
            else
                if(lgc)
                {   lgt+=lgc;
                    lgc=0;
                    nrc++;
                }
    }
    g<<lgt/nrc;
    return 0;
}