#include<iostream> #include<fstream> #include<cstring> #define DX 20080 using namespace std; fstream fin("p1.in",ios::in); char s[DX]; int main() { int a,n,i,j,nr=0; cin>>s; n=strlen(s); for(i=0;i<n;i+=8) { a=0; if(s[i]=='1') a=1; if(a==1) { if(nr!=0) { cout<<"NO\n"; return 0; } nr=0; for(j=i+7;j>i && s[j]=='0' ;j--) nr++; } else { nr--; i+=7; } } if(nr!=0) { cout<<"NO\n"; return 0; } cout<<"YES\n"; return 0; }