ans=0
n,V,c,*a=map(int,open(0).read().split())
d=[0]*-~V
b=ct=0
for v,w in zip(a[::2],a[1::2]):
    b+=v
    ct+=c
    for i in range(V-v+1):
        d[i+v]=max(d[i+v],d[i]+c*0+w)

b=ct=W=0
for v,w in sorted(zip(a[::2],a[1::2]),key=lambda x:x[0]):
    b+=v
    ct+=c
    W+=w
    if V-b>=0:ans=max(ans,ct+W+d[V-b])
print(ans)