S=input()
s=input()

SL=list(S)
SL.sort()
sl=list(s)
sl.sort()
F=0
if len(s)==2:
    if SL[0]==SL[-1] and sl[0]==sl[1] and sl[0]==SL[0]:
        F=1

ANS=S.replace(s,"A")
ans=ANS.count("A")
if F==1:
    print(ans*2-1)
    exit()
if ans>=1:
    if len(s)==1:
        print(-1)
        exit()
    else:
        print(ans)
else:
    print(ans)