n,p,k=map(int,input().split())
x=10**18
q=[-1]*(k+1)
q[0]=p
for _ in range(n):
	t,b=map(int,input().split())
	for i in reversed(range(k)):
		if q[i]!=-1:
			if t==2:
				b=q[i]
			if q[i]+b<=x:
				q[i+1]=max(q[i+1],q[i]+b)
print(q[k])