n,k,b=map(int, input().split())

a =[]

ans = 0

for i in range(n): a.append(int(input()))

for i in range(b-1,b+k-1): ans+=a[x%n]

print(ans)

from math import inf
int = int
long long = int

def main():
    n, k, b = map(int, input().split())
    a = list(map(int, input().split()))
    ans = 0
    for I in range(b-1, b+k-1, n):
        ans += a[i % n]
    print(ans)

if __name__ == "__main__":
    main()