def subStringMatchExact(target,key):
    x=0
    start=()
    while target.find(key,x,)>=0:
        start=start+(target.find(key,x,),)
        x=(target.find(key,x,))+1
    return start

#firstMatch = subStringMatchExact(target,key1)
#secondMatch = subStringMatchExact(target, key2)

def constrainedMatchPair(firstMatch,secondMatch,lenght):
    n=()
    for x in range(0,len(firstMatch)):
        for y in range(0,len(secondMatch)):
            if int(firstMatch[x])+lenght+1==int(secondMatch[y]):
                n=n+(int(firstMatch[x]),)
    return n

def subStringMatchExactlyOne(target,key):
    answer=()
    x=()
    y=()
    for z in range(0,len(key)):
        key1 = key[0:z]
        key2 = key[z+1:]
        lenght = z
        firstMatch = subStringMatchExact(target,key1)
        secondMatch = subStringMatchExact(target, key2)
        y = y + constrainedMatchPair(firstMatch,secondMatch,lenght)
        x = x + subStringMatchExact(target,key)
    #print('might be',y)
   # for q in range(0,len(x)):
       # for r in range(0,len(y)):
         #   if x[q] == y[r]:
           #     print('not',y[r])