백준_BruteForce_퇴사

n = int(input())
n_ = n
t = []
p = []

while(n_ > 0):
    splited = input().split()
    t.append(int(splited[0]))
    p.append(int(splited[1]))
    n_ -= 1
    
def fun(psum, i):
    if i > n:
        return 0
    if i == n :
        return psum    
    
    return max(fun(psum+p[i], i+t[i]), fun(psum, i+1))

print(fun(0, 0))