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)); }




void main() {
  long[] vals;
  foreach (x; 0 .. 9 + 1) foreach (y; 0 .. 9 + 1) {
    vals ~= 2L^^x * 5L^^y;
  }
  const V = cast(int)(vals.length);
  int[long] tr;
  foreach (u; 0 .. V) {
    tr[vals[u]] = u;
  }
  debug {
    writeln("V = ", V);
    writeln("vals = ", vals);
  }
  auto graph = new int[][V];
  foreach (u; 0 .. V) {
    foreach (p; [2L, 5L]) {
      if (vals[u] % p == 0) {
        graph[u] ~= tr[vals[u] / p];
      }
    }
    foreach (p; [2L, 5L]) {
      const val = min(p * vals[u], 10L^^9);
      if (vals[u] != val && (val in tr)) {
        graph[u] ~= tr[val];
      }
    }
  }
  auto rev = new int[][V];
  foreach (u; 0 .. V) {
    foreach (v; graph[u]) {
      rev[v] ~= u;
    }
  }
  
  auto dp = new int[][][](2, V, V);
  auto deg = new int[][][](2, V, V);
  auto prev = new int[][][](2, V, V);
  foreach (t; 0 .. 2) foreach (u; 0 .. V) foreach (v; 0 .. V) {
    dp[t][u][v] = -1;
    prev[t][u][v] = -1;
    deg[t][u][v] = cast(int)(graph[t ? u : v].length);
  }
  DList!int que;
  foreach (t; 0 .. 2) foreach (u; 0 .. V) {
    dp[t][u][u] = t;
    prev[t][u][u] = -2;
    que ~= t;
    que ~= u;
    que ~= u;
  }
  for (; !que.empty; ) {
    const t = que.front; que.removeFront;
    const u = que.front; que.removeFront;
    const v = que.front; que.removeFront;
    const z = dp[t][u][v];
    if (t) {
      foreach (vv; rev[v]) {
        if (!~dp[0][u][vv]) {
          if (z & 1) {
            if (--deg[0][u][vv]) {
              continue;
            }
          }
          dp[0][u][vv] = z + 1;
          prev[0][u][vv] = v;
          que ~= 0;
          que ~= u;
          que ~= vv;
        }
      }
    } else {
      foreach (uu; rev[u]) {
        if (!~dp[1][uu][v]) {
          if (z & 1) {
            if (--deg[1][uu][v]) {
              continue;
            }
          }
          dp[1][uu][v] = z + 1;
          prev[1][uu][v] = u;
          que ~= 1;
          que ~= uu;
          que ~= v;
        }
      }
    }
  }
  
  debug {
    int mx = -1;
    foreach (t; 0 .. 2) foreach (u; 0 .. V) foreach (v; 0 .. V) {
      assert(~dp[t][u][v], [t, u, v].to!string);
      chmax(mx, dp[t][u][v]);
    }
    writeln("mx = ", mx);
    stdout.flush;
  }
  
  
  int readID() {
    const val = readLong();
if(val!in tr)for(;;){}
    return tr[val];
  }
  
  {
    int u = readID;
    int v = readID;
if(u==v)for(;;){}
    foreach (iter; 0 .. 35) {
      debug {
        writefln("%s %s(%s) %s(%s): %s", 1, u, vals[u], v, vals[v], dp[1][u][v]);
        stdout.flush;
      }
      // 1: me
      {
        if (u == v) {
          return;
        }
if(vals[u]==10L^^9){writeln(vals[u]);stdout.flush;return;}
if(!(0<=u&&u<V))for(;;){}
if(!(0<=v&&v<V))for(;;){}
        const uu = prev[1][u][v];
if(!graph[u].any!(a=>a==uu))for(;;){}
if(!(0<=uu&&uu<V))for(;;){}
        writeln(vals[uu]);
        stdout.flush;
        u = uu;
      }
      // 0: enemy
      {
        if (u == v) {
          return;
        }
        const vv = readID;
if(!graph[v].any!(a=>a==vv))for(;;){}
        v = vv;
      }
    }
for(;;){}
  }
}