#include<cstdio>#include<cstring>#include<algorithm>using namespace std;const int N = 10009;struct Node {int x, y;} a[N];bool cmp(Node a, Node b) {return min(a.x, b.y) < min(b.x, a.y);}int main() {int n, i;while(~scanf("%d", &n) && n) {for(i = 0; i < n; ++i) {scanf("%d%d", &a[i].x, &a[i].y);}sort(a, a + n, cmp);int t1 = 0, t2 = 0;for(i = 0; i < n; ++i) {t1 += a[i].x;t2 = max(t1, t2) + a[i].y;}printf("%dn", t2);}return 0;}
