Codeforces Round #511 (Div. 2) B. Cover Points(思维)

#include <bits/stdc++.h>
#define ll long long
using namespace std;
int n;

int main()
{
	scanf("%d",&n);
	ll ans = 0;
	for(int i=0;i<n;i++){
		ll x,y;
		scanf("%lld%lld",&x,&y);
		if(ans < x + y)ans = x + y;
	}
	cout<<ans<<endl;
	return 0;
}