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

for _ in range(m):
    slista.append(list(map(int, input().split())))

slista.sort()
s1, s2 = slista[0]
for a1, a2 in slista[1:]:
    if s2+1 < a1:
        pp.append([s1,s2])
        s1, s2, = a1, a2
    else:
        s2=a2
pp.append([s1,s2])
for p1,p2 in pp:
    if (p1<=s and s<=p2):
        if p1 == 1:
            print(p2+1)
        elif p2 == n:
            print(p1-1)
        elif s-p1 > p2-s:
            print(p2+1)
        else:
            print(p1-1)
        break