#include<cstdio>
#define ll __int64
int main()
{
int n,w,s;
while(~scanf("%d",&n))
ll max=0,ans=0,sum=0;
while(n--)
scanf("%d%d",&w,&s);
if(w+s>max) max=w+s;
sum+=w;
}
sum-=max;
if(sum>ans) ans=sum;
printf("%I64d\n",ans);
return 0;