import sys
import io, os
input = io.BytesIO(os.read(0,os.fstat(0).st_size)).readline

n = int(input())
VT = []
for i in range(n):
    v, t = map(int, input().split())
    VT.append((v,t))

VT.sort(key=lambda x: x[0]+x[1])
dp = set()
dp.add(0)
for v, t in VT:
    nx = set()
    for k in dp:
        nx.add(k)
    m = -1
    for k in dp:
        if k < t:
            if k+v >= t:
                nx.add(k+v)
            else:
                m = max(m, k+v)
    if m != -1:
        nx.add(m)
    dp = nx
dp = list(dp)
print(max(dp))