#include<bits/stdc++.h>
using namespace std;

int64_t euler_phi(int64_t n) {
  int64_t ret = n;
  for(int64_t i = 2; i * i <= n; i++) {
    if(n % i == 0) {
      ret -= ret / i;
      while(n % i == 0) n /= i;
    }
  }
  if(n > 1) ret -= ret / n;
  return ret;
}

using ll=long long;
ll modpow(ll n,ll k,ll mod){
  ll ret=1;
  ll pw=n;
  while (k){
    if (k&1) ret=ret*pw%mod;
    pw=pw*pw%mod;
    k/=2;
  }
  return ret;
}

int main(){
  ll n,m,l;
  cin>>n>>m>>l;
  auto query=[&](ll i,ll j){
    cout<<"? "<<i<<" "<<j<<endl;
    ll ret;
    cin>>ret;
    return ret;
  };
  ll b;
  {
    ll l=0,r=1e9+10;
    while (r-l>1){
      ll mid=(l+r)/2;
      if (query(mid,1)==mid) l=mid;
      else r=mid;
    }
    b=r;
  }
  ll g=gcd(n,b);
  ll p=euler_phi(b/g);
  ll k=modpow(m,l,p);
  ll ans=query(n,k);
  cout<<"! "<<ans<<endl;
}