veliki domaci

def min_raz (a):
    min= abs(a[0] - a[1])
    for i in range (1,len(a)):
        pomocna=abs(a[i]-a[i+1])
        if pomocna<min:
            min = pomocna
    return min
def trazi(a, i, m):
    for j in range(i+1, len(a)):
        if abs(a[i]-a[j]) == m:
            return a[j]
    return -0.1

a=list()
x=bool(True)
while x:
    try:
        b=int(input())
        a.append(b)
    except x=False:
m=min_raz(a)
for i in range (0,len(a)):
    broj=trazi(a, i, m )
    if broj != -0.1:
        print('({0},{1})'.format(a[i],broj))