#蓝桥杯 平均
#输入
n = int(input())
#a数字,b代价
s = [ [] for i in range(10)]
for i in range(n):
a , b = map(int,input().split(' '))
s[a].append(b)
for i in range(10):
s[i].sort()
x = n / 10
cost = 0
for i in range(10):
for j in range(0,int(len(s[i])-x)):
cost += s[i][j]
print(cost)