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n, m, s = [int(x) for x in input().split(' ')]
ranges_left = {s:s}
ranges_right = {s:s}

for i in range(m):
    l, r = (int(x) for x in input().split(' '))
    ranges_left[r] = l
    ranges_right[l] = r
    if l <= s <= r:
        ranges_left[s] = l
        ranges_right[s] = r

dl = None
dr = None

l = s
while l >= 1:
    if l not in ranges_left:
        dl = l
        break
    l = ranges_left[l] - 1

r = s
while r <= n:
    if r not in ranges_right:
        dr = r
        break
    r = ranges_right[r] + 1

if dl is None:
    print(dr)
    exit()
if dr is None:
    print(dl)
    exit()

if abs(s - dl) <= abs(dr - s):
    print(dl)
else:
    print(dr)