f=open("input.txt","r") A=f.readline().split() f.close n=len(A); for i in range(n): A[i]= int(A[i]) B=[0]*n; k=1 while (k=n): r=n else: r=t+2*k p0=t q0=q s0=t while ((p0!=q) or (q0!=r)): if ((p0