#include <iostream>
#include <algorithm>
using namespace std;
struct st{
int a,b;
};
int N;
int current;
st ar[110];
bool compare(st a,st b)
{
if(a.a<b.a)
{
return true;
}
return false;
}
int main()
{
cin>>N;
for(int x=0; x<N; x++)
{
cin>>ar[x].a>>ar[x].b;
}
sort(ar,ar+N,compare);
for(int x=0; x<N; x++)
{
if(current < ar[x].a)
{
current = ar[x].a;
}
current += ar[x].b;
}
cout<<current;
}