#include <iostream>
#include <vector>
#include <cmath>
using namespace std;
int main() {
int n;
double x;
cin >> n >> x;
double sum = 0;
double f = 1;
for (int i = 0; i <= n; ++i) {
if (i & 1) {
sum -= pow(x, i * 2) / f;
} else {
sum += pow(x, i * 2) / f;
}
f *= (i + 1);
f *= (i + 2);
}
cout << "Cos(x) = " << sum;
return 0;
}
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