# coding:utf-8
#JSRUN引擎2.0，支持多达30种语言在线运行，全仿真在线交互输
import jieba
a=open('白鹿原.txt','r')
b=a.read()
b=jieba.lcut(b)
c={}
for i in b:
    if len(i)<=2:
        continue
    else:
        c[i]=c.get(i,0)+1
c=list(c.items())
c.sort(key=lambda x:x[1],reverse=True)
print(c[0][0])