bad=0
for X in Z:
 if len(set(X))!=50:bad+=1
 for i in range(50):
  for j in range(i+1,50):
   if (X[i]+X[j])%p not in Sset:bad+=1
print('bad',bad,'Z',len(Z))
import random
best=0
new=0
for it in range(30000):
 x=random.randrange(p)
 C=[(u-x)%p for u in U if (u-x)%p!=x]
X=[x]
 while C:
  y=random.choice(C)
  X.append(y)
  C=[z for z in C if z!=y and (y+z)%p in Sset]
 if len(X)>best:
  best=len(X)
  print('best',best,flush=True)
 if len(X)==50: 
  T=tuple(sorted(X))
  if T not in Z:new+=1
print('randombest',best,'new',new)