n, k = map(int, input().split())
lumbs = list(map(int, input().split()))
prev = None
count = 0
for i in range(len(lumbs)):
    if lumbs[i] == 0 and prev:
        count += 1
        prev = None
    elif lumbs[i] == 1:
        prev = i
if lumbs[i] == 1 and prev:
    count += 1
print(count)