import sys
input = sys.stdin.readline

N = int(input())
D = []
for i in range(N):
    A, B = map(int, input().split())
    D.append((B, A))
    
D.sort(reverse=True)
inf = 10 ** 18
pre = [inf] * N
pre[0] = 0
for i in range(N):
    dp = [inf] * N
    for j in range(N):
        dp[j] = min(dp[j], pre[j] + D[i][1] + (i - j) * D[i][0])
        if j:
            dp[j] = min(dp[j], pre[j - 1])
    dp, pre = pre, dp
        
print(pre[N//3])