n=int(input())
a=[int(i) for i in input().split()]
b=[int(i) for i in input().split()]
ans=0
op=0
from math import *
for i,j in zip(a,b):
if j==1 or 2*i<j:
ans-=1
else:
op+=1
if i==j:
ans+=(i//2)*ceil(i/2)
elif 2*i==j:
ans+=i**2
else:
ans+=(j//2)*ceil(j/2)
print(-1 if op==0 else ans)Lexical Sorting Reloaded | 1514A - Perfectly Imperfect Array |
580A- Kefa and First Steps | 1472B- Fair Division |
996A - Hit the Lottery | MSNSADM1 Football |
MATCHES Playing with Matches | HRDSEQ Hard Sequence |
DRCHEF Doctor Chef | 559. Maximum Depth of N-ary Tree |
821. Shortest Distance to a Character | 1441. Build an Array With Stack Operations |
1356. Sort Integers by The Number of 1 Bits | 922. Sort Array By Parity II |
344. Reverse String | 1047. Remove All Adjacent Duplicates In String |
977. Squares of a Sorted Array | 852. Peak Index in a Mountain Array |
461. Hamming Distance | 1748. Sum of Unique Elements |
897. Increasing Order Search Tree | 905. Sort Array By Parity |
1351. Count Negative Numbers in a Sorted Matrix | 617. Merge Two Binary Trees |
1450. Number of Students Doing Homework at a Given Time | 700. Search in a Binary Search Tree |
590. N-ary Tree Postorder Traversal | 589. N-ary Tree Preorder Traversal |
1299. Replace Elements with Greatest Element on Right Side | 1768. Merge Strings Alternately |