import std.conv, std.functional, std.range, std.stdio, std.string;
import std.algorithm, std.array, std.bigint, std.bitmanip, std.complex, std.container, std.math, std.mathspecial, std.numeric, std.regex, std.typecons;
import core.bitop;

class EOFException : Throwable { this() { super("EOF"); } }
string[] tokens;
string readToken() { for (; tokens.empty; ) { if (stdin.eof) { throw new EOFException; } tokens = readln.split; } auto token = tokens.front; tokens.popFront; return token; }
int readInt() { return readToken.to!int; }
long readLong() { return readToken.to!long; }
real readReal() { return readToken.to!real; }

bool chmin(T)(ref T t, in T f) { if (t > f) { t = f; return true; } else { return false; } }
bool chmax(T)(ref T t, in T f) { if (t < f) { t = f; return true; } else { return false; } }

int binarySearch(alias pred, T)(in T[] as) { int lo = -1, hi = cast(int)(as.length); for (; lo + 1 < hi; ) { const mid = (lo + hi) >> 1; (unaryFun!pred(as[mid]) ? hi : lo) = mid; } return hi; }
int lowerBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a >= val)); }
int upperBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a > val)); }


int nand(int x, int y) {
  return (x & y) ^ 1;
}

bool solve() {
  auto A = new string[6];
  foreach (i; 0 .. 6) {
    A[i] = readToken;
  }
  foreach (p; 0 .. 1 << 6) {
    auto xs = new int[6];
    foreach (i; 0 .. 6) {
      xs[i] = p >> i & 1;
    }
    bool ok = true;
    foreach (i; 0 .. 6) foreach (j; 0 .. 6) if (A[i] == A[j]) {
      ok = ok && (xs[i] == xs[j]);
    }
    if (ok) {
      if (nand(
        nand(nand(xs[0], xs[1]), xs[2]),
        nand(nand(xs[3], xs[4]), xs[5])
      )) {
        debug {
          writeln(xs);
        }
        return true;
      }
    }
  }
  return false;
}

void main() {
  try {
    for (; ; ) {
      const ans = solve;
      writeln(ans ? "YES" : "NO");
    }
  } catch (EOFException e) {
  }
}