import sequtils,strutils,algorithm,sets

type
    ie = tuple[v,t : int]
var
    N = stdin.readline.parseInt
    kinjo = newSeq[ie](N)
    s = initSet[int](32768)
    s2 = s
    a,b : int
    ans = newSeq[int](0)
    Mi : ie
for n in 0..<N:
    (a,b) = stdin.readline.split.map(parseInt)
    kinjo[n] = ((a,b))
    if Mi.t < a:
        Mi = (a,b)

kinjo = kinjo.sortedByIt(it.t)
kinjo.add(Mi)
for k in kinjo:
    s2.clear
    for i in s:
        if i >= k.t:
            break
        else:
            s2.incl(i + k.v)
    s2.incl(k.v)
    s = union(s,s2)
for t in s:
    ans.add(t)
echo max(ans)