N = int(input())
turn = []
for _ in range(N):
    a,b = list(map(int,input().split()))
    turn.append((a,b))

INF = 10**18
def f(n,atk):
    if(n == N):return 0 if atk == 0 else -INF

    # 攻撃しない
    ret = f(n+1,atk) + turn[n][0] * atk
    # 攻撃する
    ret = max(ret,f(n+1,atk-1) + turn[n][1])

    return ret

ans = 0
for i in range(1,N+1):
    ans = max(ans, f(0,i))
print(ans)