N = int(input())
k = []
for n in range(N):
    a, b = map(int, input().split())
    k.append((a, b))
k.sort(key=lambda it: it[0] + it[1])
s = set()
for ik in k:
    s2 = set()
    for i in s:
        if i >= ik[1]:
            break
        else:
            s2.add(i + ik[0])
    s2.add(ik[0])
    s |= s2
ans = list(s)
print(max(ans))