n,m,s = input().split(" ")
s = int(s)
p = [[s]]
for x in range(int(m)):
    t,r = input().split(" ")
    t= int(t)
    r = int(r)
    p.append([t,r])
p.sort()
if p[p.index([s])+1][0]==s:
    te = p.index([s])
    p[p.index([s])]=p[p.index([s])+1]
    p[te+1]=[s]
np = p[p.index([s])-1][0]-1
nk = p[p.index([s])-1][1]+1
lp = p[:p.index([s])-1]
lp.reverse()
lk = p[p.index([s]):]
lk.remove([s])
if lk!=[]:
    for x in lk:
        if nk==x[0]:
            nk=x[1]+1
if lp!=[]:
    for x in lp:
        if np==x[1]:
            np=x[0]-1
if (-s+nk<s-np and nk<int(n)) or np<1:
    print(nk)
else:
    print(np)