a=int(input())
m=[]
l=[]
result=0
for i in range(a):
b,c=input().split()
if b not in m:
m.append(b)
l.append([])
l[-1].append(int(c))
elif b in m:
l[m.index(b)].append(int(c))
for i in range(len(l)):
l[i].sort()
if len(l[i])>=2:
result=result+l[i][-1]+l[i][-2]
else:
result+=l[i][-1]
print(result)