#include <iostream>
#include <vector>
#include <algorithm>
#include <functional>
#include <cstdint>
 
using namespace std;
 
int main()
{
    uint64_t x; //на всякий случай 64
	vector<int> v;
 
	while ( cin >> x ) {
		v.clear();
 
		for (uint64_t t = x; t; t /= 10)
			v.push_back(t % 10);
 
		auto it = v.crbegin();
		for (; it != v.crend(); ++it)
			if ( any_of( it + 1, v.crend(), bind2nd( less<int>(), *it ) ) )
				break;
		if (it == v.crend()) cout << "OK: " << x << endl;
	}
    return 0;
}

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