def read_data():
    N = int(input())
    VT = []
    for n in range(N):
        v, t = map(int, input().split())
        VT.append((v + t, v, t))
    return N, VT

def solve(N, VT):
    VT.sort(reverse=True)
    upper = min(VT[0][0], sum(v for vt, v, t in VT) + 1)
    lower = 1
    while lower + 1 < upper:
        mid = (upper + lower) // 2
        if is_valid(mid, VT):
            lower = mid
        else:
            upper = mid
    return lower

def is_valid(val, VT):
    used = [False] * len(VT)
    lower = val
    upper = float('inf')
    return dfs(lower, upper, VT, used)

def dfs(lower, upper, VT, used):
    '''VTのうち、used でないものを使って、lower 以上、upper 未満の選び方をできるかを返す。
    '''
    for i, (val, v, t) in enumerate(VT):
        if val < lower:
            return False
        if used[i] or v >= upper:
            continue
        if v >= lower:
            return True
        used[i] = True
        result = dfs(lower - v, min(upper, t), VT, used)
        used[i] = False
        if result:
            return True
    return False

N, VT = read_data()
print(solve(N, VT))