#include <iostream>
using namespace std;
const int TEN = 10;
void applyDiscount(int &n) {
if (n < 50) {
n -= n / TEN;
} else if (n <= TEN * TEN) {
n -= n / TEN * 2;
}
}
int main() {
int n;
cin >> n;
applyDiscount(n);
cout << n;
return 0;
}
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