#include <iostream>

using namespace std;
int c;
void A();
void B();
void C();

void gc()
{
    cin >> c;
}
void S()
{
    C();
    gc();
    if (!(c == '0' || c == '1')) {
        throw 1;
    }
}
void A()
{
    if (c != '0' && c != '1') {
        gc();
        A();

        if (!(c == '0' || c == '1')) {
            throw 1;
        }
    }
}
void B()
{
    if (c != '1') {
        A();
        gc();
        if (c != '1') {
             throw 1;
        }
    }
}
void C()
{
    B();
    gc();
    if (c != '0' && c != '1') {
        throw 1;
    }
}
int main(void)
{
    try {
        gc();
        S();
    } catch (int) {
        cout << "wrong" << endl;
        return 0;
    }
    cout << "OK" << endl;
    return 0;
}