// editor5
#include <iostream>
#include <vector>
using namespace std;

int main()
{
    vector <float> d;
    vector <float> f;
    
    float td = 0.0, tf = 0.0, e = 0.0;
    
    int n;
    cin >> n;
    
    int f = 0;
    
    if(!(n>=1 && n<=50))
    return 0;
    
    for(int i=0;i<n;i++)
    {
        cin >> d[i] >> f[i];
        
        if(!(d[i]>0 && d[i]<=1000))
        f = 1;
        if(!(f[i]>0 && f[i]<=500))
        f = 2;
        
        td += d[i];
        tf += f[i];
    }
    
}