#include <stdio.h>

double getFinalPos(double y) {
	double p=650-26*200*(5+1);
	double k=704-y;
	return (p+k)*649/(649+k);
}

int main(void) {
	double y;
	scanf("%lf",&y);
	printf("%.60f\n",getFinalPos(y));
	return 0;
}