n, m, s = map(int, input().split())
vecs = []

for _ in range(m):
	start, end = map(int, input().split())
	
	vecs.append((start, end))

def find_empty(x, y):
	global vecs, s, n
	if x <= 0 or x > n or x == s :
		x = -1
	if y <= 0 or y > n or y == s:
		y = -1
	
	for start, end in vecs:
		if x >= start and x <= end:
			x = -1
		if y >= start and y <= end:
			y = -1
		
		
	return x if x > 0 else y

for i in range(1, n+1):
	left = s - i
	right = s + i
	
	x = find_empty(left, right)
	if x  > 0:
		print(x)
		break