90pts求调

#include<bits/stdc++.h>  
using namespace std;  
int n;  
int main(){  
	cin>>n;  
	int b[n+10],max[n+10];  
	double a[n+10];  
	for(int i=1;i<=n;i++){  
		cin>>a[i]>>b[i];  
		if(a[i]/2<=b[i]) max[i]=b[i];
		else max[i]=a[i]-b[i];
	}
	sort(max+1,max+1+n);
	cout<<max[n]+max[n-1];
	return 0;
}