#include <iostream>
#include <cmath>
using namespace std;
int main()
{
    int N, sumv=0,summv=0;
    cout<<" Dwse arithmo askisewn"<<endl;
    cin>>N;
   int i, vathmos, megistosvathmos;
   for (i=1;i<=N;i++)
   {
  cout<<"Dwse vathmo gia askisi"<<endl;
  cin>>vathmos;
  cout<<"Dwse megisto vathmo askisis"<<endl;
  cin>>megistosvathmos;
  sumv=vathmos+sumv;
  summv=summv+megistosvathmos;}
  cout<<(sumv/summv)*100;
  
  system ("PAUSE");
  return 0;
}