#include<bits/stdc++.h>   using namespace std;   #define ll long long   #define ld long double   #define For(i,x,y) for(ll i = (x);i <= (y);++i)   #define FOr(i,x,y) for(ll i = (x);i >= (y);--i)   #define fi first   #define se second   #define pa pair<ll,ll>   #define mk make_pair   #define pb push_back   #define clr(a,b) memset(a,b,sizeof(a))   #define cpy(a,b) memcpy(a,b,sizeof(b))   #define y1 y11111111111111111111   #define debug puts( @@@@@@@@@@@@@@@@@@@@ )   #define NO puts( NO )   #define YES puts( YES )   #define Yes puts( Yes )   #define No puts( No )   inline ll read()   {    ll x = 0,f = 1;char ch = getchar();    while(ch <  0  || ch >  9 ){if(ch ==  - )f = -1;ch = getchar();}    while(ch >=  0  && ch <=  9 ){x = x*10+ch- 0 ;ch = getchar();}    return x*f;   }   char s[999];   int main()   {    while (scanf( %s ,s)!=EOF)    {     if (s[1]== s ) puts( NO ),fflush(stdout);    }   }