# ╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬
# ╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬
# ╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬     ╬╬╬╬╬
# ╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬ ╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬          ╬   ╬
# ╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬ ╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬     ╬╬
# ╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬ ╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬  ╬ ╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬     ╬
# ╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬  ╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬ ╬    ╬╬╬╬╬╬╬   ╬╬╬╬╬╬╬╬╬╬      ╬
# ╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬ ╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬  ╬   ╬╬╬╬╬╬╬  ╬      ╬╬╬╬  ╬╬╬╬
# ╬╬╬╬╬╬╬╬╬╬╬╬╬ ╬╬ ╬    ╬╬╬╬╬╬╬╬╬        ╬ ╬        ╬╬ ╬╬╬
# ╬╬╬╬╬╬╬╬╬╬╬╬╬╬    ╬     ╬╬╬           ╬ ╬╬╬    ╬  ╬╬  ╬╬╬╬╬╬╬╬
# ╬╬╬╬╬╬ ╬╬╬╬╬╬╬╬                        ╬╬╬╬╬╬╬╬╬  ╬   ╬╬╬╬╬╬╬╬   ╬╬╬
# ╬╬  ╬╬╬  ╬╬╬╬     ╬╬╬╬╬                  ╬╬╬╬╬╬╬       ╬╬ ╬╬╬╬  ╬    ╬
# ╬╬      ╬   ╬╬╬╬╬╬╬╬╬╬╬ ╬                 ╬╬╬╬         ╬  ╬╬╬           ╬
# ╬╬       ╬╬╬╬╬    ╬                                  ╬    ╬╬               ╬
# ╬╬     ╬╬╬╬╬╬╬╬                                    ╬╬    ╬
# ╬╬     ╬╬╬╬╬╬╬╬╬╬╬╬╬╬                      ╬          ╬
# ╬╬╬╬  ╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬                                      ╬
# ╬╬╬╬╬       ╬╬╬╬╬                                          ╬
# ╬╬╬╬╬╬╬                                    ╬╬╬
# ╬╬╬╬╬╬╬╬╬╬                          ╬  ╬╬╬╬╬╬╬╬
# ╬╬╬╬╬╬╬╬╬ ╬  ╬                  ╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬         ╬
# ╬╬╬╬╬╬╬╬╬╬╬╬                  ╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬        ╬
# ╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬                ╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬       ╬
# ╬    ╬╬╬╬╬╬╬╬╬╬╬                 ╬╬╬╬╬╬╬╬╬╬

n = int(input())
v = list(map(int, input().split()))
c = list(map(int, input().split()))

ans = 0
for i in range(n):
    if v[i] - c[i] > 0:
        ans += v[i] - c[i]

print(ans)

### FIXED CODE ###

##########################################################...#.....#...#.....
########################################.#.################....#.............
#########################################.#..################....##..........
###################.#####################..#.##################.....#........
####################.#####################.#..#######..##########......#.....
####################..####################....####...#.....######.###........
#####################################....#...##...###..#.......##..####......
################.##.#....#########........#.#........##.###..................
#################.#..#....##..#..........#.##........##.#######..............
########.########.....#.....##.............####...#..#...########..#.........
#########.########.....#...................########..#...########...#.##.....
#####..###..####.....#####..................#######.......##.####..#....#....
#####.....#.....##########...................#####........#..###..#.......##.
#####........#####.##....##.#............................###.##..#...........
#####......######.........................#.................##...............
#####.....########....................................##....#................
#####.....##############......................#...........##.#...............
######...###############.....................................................
########..##############......................................#..............
########.......#####..........................................#..............

a, b, t = map(int, input().split())
print(b * (t // a))