#include <bits/stdc++.h>
using namespace std;
int main() {
stack <int> st;
string s;
int x;
while(cin >> s)
{
if(s=="push")
{
cin >> x;
st.push(x);
cout << "ok";
}
if(s=="push")
{
}
if(s=="push")
{
}
if(s=="push")
{
}
}
return 0;
}
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